### Install b2sdk with pip

Source: https://github.com/backblaze/b2-sdk-python/blob/master/README.md

Use this command to install the SDK. Ensure you have pip installed.

```bash
pip install b2sdk
```

--------------------------------

### Install Development Tools

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Install the necessary development tools, `nox` and `uv`, using pip. These tools are essential for running development automation sessions.

```bash
pip install nox uv
```

--------------------------------

### Specify b2sdk version in requirements.txt

Source: https://github.com/backblaze/b2-sdk-python/blob/master/README.md

Pin the b2sdk version in your requirements.txt file to ensure compatibility. This example allows versions 2.x.x.

```text
b2sdk>=2,<3
```

--------------------------------

### Initialize Synchronizer with Custom Options

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/sync.md

Initializes the Synchronizer with specific configurations for file comparison, handling of newer files, and policies for managing older files. This example sets the comparison mode to SIZE, a threshold of 10 bytes, replaces newer files, and keeps deleted files for 10 days.

```python
>>> from b2sdk.v3 import ScanPoliciesManager
>>> from b2sdk.v3 import parse_folder
>>> from b2sdk.v3 import Synchronizer, SyncReport
>>> from b2sdk.v3 import KeepOrDeleteMode, CompareVersionMode, NewerFileSyncMode
>>> import time
>>> import sys

>>> source = '/home/user1/b2_example'
>>> destination = 'b2://example-mybucket-b2'

>>> source = parse_folder(source, b2_api)
>>> destination = parse_folder(destination, b2_api)

>>> policies_manager = ScanPoliciesManager(exclude_all_symlinks=True)

>>> synchronizer = Synchronizer(
        max_workers=10,
        policies_manager=policies_manager,
        dry_run=False,
        allow_empty_source=True,
        compare_version_mode=CompareVersionMode.SIZE,
        compare_threshold=10,
        newer_file_mode=NewerFileSyncMode.REPLACE,
        keep_days_or_delete=KeepOrDeleteMode.KEEP_BEFORE_DELETE,
        keep_days=10,
    )
```

--------------------------------

### Pinning Dependencies for Internal Interface

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api_types.md

When using the internal interface of b2sdk, it is recommended to pin your dependencies to a specific minor version to avoid breaking changes. This example shows how to add this to your requirements.txt file.

```text
b2sdk>=4.5.6,<4.6.0
```

--------------------------------

### Load Bash Completions from a Directory

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/bash_completion.md

This script iterates through a directory and sources any files found, enabling bash completion for tools installed in that directory. Ensure this is placed in your `~/.bash_completion` file.

```bash
if [ -d "$HOME/.bash_completion.d" ]; then
	for file in "$HOME/.bash_completion.d/"*
	do
		source "$file" >/dev/null 2>&1
	done
fi
```

--------------------------------

### Initialize Synchronizer with MODTIME Comparison and SKIP Mode

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/sync.md

Configures the Synchronizer to compare files based on modification time (MODTIME) with a threshold of 10 seconds and to skip synchronization if the source file is newer than the destination. This setup is useful for avoiding unnecessary updates when only minor time differences exist or when explicit skipping is desired.

```python
>>> synchronizer = Synchronizer(
        max_workers=10,
        policies_manager=policies_manager,
        dry_run=False,
        allow_empty_source=True,
        compare_version_mode=CompareVersionMode.MODTIME,
        compare_threshold=10,  # in seconds
        newer_file_mode=NewerFileSyncMode.SKIP,

```

--------------------------------

### Retrieve Bucket by Name

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/tutorial.md

Get a Bucket object for an existing B2 bucket by providing its name. This allows for operations like listing files.

```python
b2_api.get_bucket_by_name("example-mybucket-b2-1",)
```

--------------------------------

### Perform Synchronization and Report Actions

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/sync.md

Executes the synchronization process between source and destination folders using the configured Synchronizer. Reports actions like uploads and deletions to standard output. This example demonstrates the outcome when a file exists in the destination but not the source, leading to its deletion and hiding for 10 days.

```python
>>> no_progress = False
>>> with SyncReport(sys.stdout, no_progress) as reporter:
        synchronizer.sync_folders(
            source_folder=source,
            dest_folder=destination,
            now_millis=int(round(time.time() * 1000)),
            reporter=reporter,
        )
upload f1.txt
delete hello.txt (old version)
hide   hello.txt
```

--------------------------------

### Obtain Download Version Object by ID

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Download a file by its ID and get the `DownloadVersion` object, which contains metadata about the downloaded file.

```python
>>> file_id = '4_z5485a1682662eb3e60980d10_f113f963288e711a6_d20190404_m065910_c002_v0001095_t0044'
>>> downloaded_file = b2_api.download_file_by_id(file_id)
>>> download_version = downloaded_file.download_version
```

--------------------------------

### Set Nox Python Versions

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Configure the Python versions used by `nox` sessions by setting the `NOX_PYTHONS` environment variable. This example sets sessions to run on Python 3.12 and 3.14.

```bash
export NOX_PYTHONS=3.12,3.14
```

--------------------------------

### No Continuation - create_file

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/advanced.md

Explicitly disables continuation for a file upload, forcing the SDK to start a new large file upload regardless of existing unfinished uploads. Manual or auto continuation can still be attempted in subsequent calls.

```python
>>> bucket.create_file(input_sources, remote_name, file_info, auto_continue=False)
```

--------------------------------

### Run Nox Format Session (Re-using Environment)

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Execute the `format` session with `nox`, demonstrating the re-use of an existing virtual environment for faster execution.

```bash
$ nox -s format
nox > Running session format
nox > Re-using existing virtual environment at .nox/format.
...
```

--------------------------------

### Build documentation with nox and watch for changes

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Build the project documentation and automatically recompile when changes are detected in the source code or documentation files.

```bash
nox -s doc
```

--------------------------------

### Prepare B2 SDK Account

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Initializes the B2 SDK with in-memory account information and authorizes the account using application key credentials.

```python
>>> from b2sdk.v3 import *
>>> info = InMemoryAccountInfo()
>>> b2_api = B2Api(info, cache=AuthInfoCache(info))
>>> application_key_id = '4a5b6c7d8e9f'
>>> application_key = '001b8e23c26ff6efb941e237deb182b9599a84bef7'
>>> b2_api.authorize_account("production", application_key_id, application_key)
```

--------------------------------

### Build Documentation and Watch for Changes

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Build the project documentation and enable watching for changes in both the documentation source and the project's source code. This is useful for iterative documentation development.

```bash
$ nox -s doc
```

--------------------------------

### Make Release Commit

Source: https://github.com/backblaze/b2-sdk-python/blob/master/README.release.md

Run this command to initiate the release commit process. Replace X.Y.Z with the target version number.

```bash
nox -s make_release_commit -- X.Y.Z
```

--------------------------------

### Get File Metadata

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Retrieve metadata for a specific file version in B2 Cloud Storage using its file ID. The metadata includes details such as account ID, file ID, content length, SHA1 hash, content type, and server-side encryption information.

```python
>>> file_id = '4_z5485a1682662eb3e60980d10_f113f963288e711a6_d20190404_m065910_c002_v0001095_t0044'
>>> file_version = b2_api.get_file_info(file_id)
>>> file_version.as_dict()
{'accountId': '451862be08d0',
 'action': 'upload',
 'bucketId': '5485a1682662eb3e60980d10',
 'contentLength': 1870579,
 'contentSha1': 'd821849a70922e87c2b0786c0be7266b89d87df0',
 'contentType': 'application/pdf',
 'fileId': '4_z5485a1682662eb3e60980d10_f113f963288e711a6_d20190404_m065910_c002_v0001095_t0044',
 'fileInfo': {'how': 'good-file', 'sse_c_key_id': 'user-generated-key-id'},
 'fileName': 'dummy_new.pdf',
 'uploadTimestamp': 1554361150000,
 "serverSideEncryption": {"algorithm": "AES256",
                          "mode": "SSE-C"},
 }
```

--------------------------------

### Run Nox Format Session

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Use `nox` to format the code. This command initiates the `format` session, which typically uses `ruff` for code formatting.

```bash
$ nox -s format
```

--------------------------------

### Configure PATH and Bash Completion

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/bash_completion.md

Add this snippet to your `~/.bashrc` to ensure the `~/bin` directory is in your PATH before bash completion is loaded, and to enable bash completion features if not already enabled.

```bash
if [ -d ~/bin ]; then
    PATH="$HOME/bin:$PATH"
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi
```

--------------------------------

### Run Nox Format Session (Without Virtual Environment)

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Run the `format` session using `nox` without creating or re-using a virtual environment. This can be useful for specific CI or testing scenarios.

```bash
$ nox --no-venv -s format
nox > Running session format
...
```

--------------------------------

### Run all linters with nox

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Execute all configured linters for the project by running the 'lint' nox session.

```bash
nox -s lint
```

--------------------------------

### Build documentation non-interactively

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Build the project documentation once without interactive prompts or watching for changes.

```bash
nox --non-interactive -s doc
```

--------------------------------

### Initialize InMemoryAccountInfo

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/tutorial.md

Create an InMemoryAccountInfo object to store credentials, tokens, and cache in memory. This is the first step to using the b2sdk.

```python
from b2sdk.v3 import InMemoryAccountInfo
info = InMemoryAccountInfo()  # store credentials, tokens and cache in memory
```

--------------------------------

### Run All Tests

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Execute the test suite on all available Python versions by running the `test` session with `nox`. This ensures compatibility across different environments.

```bash
$ nox -s test
```

--------------------------------

### Build Documentation Non-interactively

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Build the project documentation in a non-interactive mode using `nox`. This command is suitable for automated build processes where user interaction is not possible.

```bash
$ nox --non-interactive -s doc
```

--------------------------------

### Prioritize Remote Sources for File Synthesis

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/advanced.md

Setting `prioritize='remote'` instructs the planner to use remote sources whenever available, minimizing downloads.

```python
>>> planner.create_file(input_sources, remote_name, file_info, prioritize='remote')
# planner parts: cloud[A, D], local[D, E]
```

--------------------------------

### Create a New Bucket

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/tutorial.md

Create a new bucket in your B2 account. Bucket names must be unique across all B2 accounts. Specify 'allPublic' or 'allPrivate' for the bucket type.

```python
bucket_name = 'example-mybucket-b2-1'
bucket_type = 'allPublic'  # or 'allPrivate'

b2_api.create_bucket(bucket_name, bucket_type)
```

--------------------------------

### Download File

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Demonstrates how to download a file using a `FileVersion` object, which is equivalent to using the `download_file_by_id` method.

```APIDOC
## Download (only for `b2sdk.v3.FileVersion`)

This method downloads the content of a file represented by a `FileVersion` object.

### Method
```python
file_version.download()
```

### Equivalent Operation
```python
b2_api.download_file_by_id(file_version.id_)
```
```

--------------------------------

### Obtain File Version Objects by Listing

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

List files within a bucket, optionally filtering by prefix and retrieving only the latest versions. This yields `FileVersion` and folder name pairs.

```python
>>> for file_version, folder_name in bucket.ls(latest_only=True, prefix='dir_name'):
>>>     ...
```

--------------------------------

### Create a Bucket

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Creates a new bucket with a specified name and type (e.g., 'allPublic' or 'allPrivate'). The bucket name must be unique across all B2 accounts.

```python
>>> bucket_name = 'example-mybucket-b2-1'  # must be unique in B2 (across all accounts!)
>>> bucket_type = 'allPublic'  # or 'allPrivate'

>>> b2_api.create_bucket(bucket_name, bucket_type)
Bucket<346501784642eb3e60980d10,example-mybucket-b2-1,allPublic>
```

--------------------------------

### Synthesize File from Local and Remote Parts

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/advanced.md

Use `create_file()` with an iterable of `WriteIntent` objects to combine data from remote parts and local files. This supports large output objects and can reduce data transfer.

```python
>>> bucket = b2_api.get_bucket_by_name(bucket_name)
>>> def generate_input():
...     yield WriteIntent(
...         CopySource('4_z5485a1682662eb3e60980d10_f113f963288e711a6_d20190404_m065910_c002_v0001095_t0044', offset=0, length=lengthC),
...         destination_offset=0,
...     )
...     yield WriteIntent(
...         UploadSourceLocalFile('my_local_path/to_file.txt'), # length = offsetF - offsetB
...         destination_offset=offsetB,
...     )
...     yield WriteIntent(
...         CopySource('4_z5485a1682662eb3e60980d10_f113f963288e711a6_d20190404_m065910_c002_v0001095_t0044', offset=0, length=offsetG-offsetD),
...         destination_offset=offsetD,
...     )
...
>>> file_info = {'how': 'good-file'}
>>> bucket.create_file(generate_input(), remote_name, file_info)
<b2sdk._internal.file_version.FileVersion at 0x7fc8cd560552>
```

--------------------------------

### Run all tests with nox

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Execute the test suite across all available Python versions using the 'test' nox session.

```bash
nox -s test
```

--------------------------------

### Run nox format session

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Use nox to format the code. This command runs the 'format' session provided by nox.

```bash
nox -s format
```

--------------------------------

### Prioritize Local Sources for File Synthesis

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/advanced.md

When creating a file from multiple sources, setting `prioritize='local'` tells the planner to prefer local files over remote ones for overlapping ranges, minimizing uploads.

```python
>>> bucket.create_file(input_sources, remote_name, file_info, prioritize='local')
# planner parts: cloud[A, B], local[B, C], remote[C, D], local[D, E]
```

--------------------------------

### Create a changelog entry

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Use the 'towncrier create' command to generate a changelog file for a specific issue and type.

```bash
towncrier create -c 'write your description here' 157.fixed.md
```

--------------------------------

### Manual Continuation with Callback - create_file_stream

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/advanced.md

Similar to create_file, use a callback to capture the large_file_id for manual continuation. This is specifically for the streamed version of create_file, supporting local sources only.

```python
>>> def large_file_callback(large_file):
...     # storage is not part of the interface - here only for demonstration purposes
...     storage.store({'name': remote_name, 'large_file_id': large_file.id})
>>> bucket.create_file_stream(input_sources, remote_name, file_info, large_file_callback=large_file_callback)
# ...
>>> large_file_id = storage.query({'name': remote_name})[0]['large_file_id']
>>> bucket.create_file_stream(input_sources, remote_name, file_info, large_file_id=large_file_id)
```

--------------------------------

### Copy File

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Illustrates how to copy an existing file to a new location or with a new name within the bucket. It also covers copying parts of a file and handling large files.

```APIDOC
## Copy file

This operation copies a file to a new name or location within the same bucket. It supports copying specific parts of a file and has considerations for large files.

### Method
```python
new_file_version = bucket.copy(file_id, 'f2_copy.txt')
bucket.copy(file_id, 'f2_copy.txt', offset=1024, length=2048)
```

### Parameters
- `file_id` (str): The ID of the source file to copy.
- `new_file_name` (str): The name for the new copied file.
- `offset` (int, optional): The starting byte offset for copying a portion of the file.
- `length` (int, optional): The number of bytes to copy, starting from the offset. Required if `offset` is not zero.
- `max_copy_part_size` (int, optional): The maximum size for copy parts, defaults to 5GB.

### Considerations
- If `content_length` is not provided and the file is larger than 5GB, the copy operation may fail.
- `max_copy_part_size` can be used to control how large files are copied.
- SSE-C encrypted source files require the proper key to be provided.
```

--------------------------------

### Obtain File Version Objects

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Explains how to obtain `FileVersion` and `DownloadVersion` objects, which represent files and provide high-level access to file manipulation methods.

```APIDOC
## Obtain file representing objects

These sections describe how to get `FileVersion` and `DownloadVersion` objects, which encapsulate file information and provide methods for interacting with files.

### `b2sdk.v3.FileVersion`

#### By id
Retrieves a `FileVersion` object using its unique file ID.

```python
file_version = b2_api.get_file_info(file_id)
```

#### By listing
Lists files within a bucket, optionally filtering by latest version and prefix, returning `FileVersion` objects.

```python
for file_version, folder_name in bucket.ls(latest_only=True, prefix='dir_name'):
    ...
```

### `b2sdk.v3.DownloadVersion`

#### By id
Downloads a file by its ID and returns a `DownloadVersion` object.

```python
downloaded_file = b2_api.download_file_by_id(file_id)
download_version = downloaded_file.download_version
```

#### By name
Downloads a file by its name from a specified bucket and returns a `DownloadVersion` object.

```python
downloaded_file = bucket.download_file_by_name(b2_file_name)
download_version = downloaded_file.download_version
```
```

--------------------------------

### Run nox format session without virtual environment

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Execute the 'format' nox session without creating or using a virtual environment.

```bash
nox --no-venv -s format
```

--------------------------------

### Initialize B2Api

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/tutorial.md

Create a B2Api object using the AccountInfo object. This object is used for account-level operations.

```python
from b2sdk.v3 import B2Api
b2_api = B2Api(info)
```

--------------------------------

### Run All Linters

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Execute all available linters by running the `lint` session with `nox`. This command helps identify potential issues with code maintainability.

```bash
$ nox -s lint
```

--------------------------------

### Initialize Synchronizer for Deletion Mode

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/sync.md

Initializes the Synchronizer with `keep_days_or_delete=KeepOrDeleteMode.DELETE`. This configuration ensures that files deleted from the source are permanently removed from the destination without any retention period.

```python
>>> synchronizer = Synchronizer(
        max_workers=10,
        policies_manager=policies_manager,
        dry_run=False,
        allow_empty_source=True,
        compare_version_mode=CompareVersionMode.SIZE,
        compare_threshold=10,  # in bytes
        newer_file_mode=NewerFileSyncMode.REPLACE,
        keep_days_or_delete=KeepOrDeleteMode.DELETE,
    )

>>> with SyncReport(sys.stdout, no_progress) as reporter:
    synchronizer.sync_folders(
        source_folder=source,
        dest_folder=destination,
        now_millis=int(round(time.time() * 1000)),
        reporter=reporter,
    )
delete f1.txt
delete f1.txt (old version)
delete hello.txt (old version)
upload f2.txt
delete hello.txt (hide marker)
```

--------------------------------

### Obtain Download Version Object by Name

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Download a file by its name from a bucket and obtain its `DownloadVersion` object. Ensure the bucket object is retrieved first.

```python
>>> bucket = b2_api.get_bucket_by_name(bucket_name)
>>> b2_file_name = 'dummy_new.pdf'
>>> downloaded_file = bucket.download_file_by_name(b2_file_name)
>>> download_version = downloaded_file.download_version
```

--------------------------------

### List Buckets

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Retrieves and prints a list of all buckets associated with the authorized account, displaying their ID, type, and name.

```python
>>> b2_api.list_buckets()
[Bucket<346501784642eb3e60980d10,example-mybucket-b2-1,allPublic>]
>>> for b in b2_api.list_buckets():
        print('%s  %-10s  %s' % (b.id_, b.type_, b.name))
346501784642eb3e60980d10  allPublic   example-mybucket-b2-1
```

--------------------------------

### Public Interface Version Pinning

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/markup-test.rst

If you only use public interfaces, pin your dependencies to a range that excludes the next major version.

```text
>=4.5.6;<5.0.0
```

--------------------------------

### Run Tests on Specific Python Version

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Run the test suite on a specific Python version, such as 3.10, by using the `test-3.10` session with `nox`.

```bash
$ nox -s test-3.10
```

--------------------------------

### Run tests on a specific Python version

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Run the test suite on a particular Python version, e.g., Python 3.10, using the 'test-3.10' nox session.

```bash
nox -s test-3.10
```

--------------------------------

### Prioritize Local Verification for File Synthesis

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/advanced.md

Using `prioritize='local_verification'` splits remote ranges to allow for checksum verification against matching local ranges, ensuring data integrity.

```python
>>> bucket.create_file(input_sources, remote_name, file_info)
# or
>>> bucket.create_file(input_sources, remote_name, file_info, prioritize='local_verification')
# planner parts: cloud[A, B], cloud[B, C], cloud[C, D], local[D, E]
```

--------------------------------

### Synchronization with Small File Changes

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/sync.md

Runs synchronization when a file has been modified but the change is below the `compare_threshold`. With `compare_threshold=10` bytes, minor changes will not trigger a file replacement.

```python
>>> with SyncReport(sys.stdout, no_progress) as reporter:
        synchronizer.sync_folders(
            source_folder=source,
            dest_folder=destination,
            now_millis=int(round(time.time() * 1000)),
            reporter=reporter,
        )
```

--------------------------------

### Implement Custom AccountInfo

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/account_info.md

Inherit from UrlPoolAccountInfo to create a custom AccountInfo for server-side applications. This class provides groundwork for url pool functionality.

```python
from b2sdk.v3 import UrlPoolAccountInfo
class MyAccountInfo(UrlPoolAccountInfo):
        ...
```

--------------------------------

### Auto Continuation - create_file

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/advanced.md

Enables automatic continuation for large file uploads. The SDK attempts to find and resume an unfinished upload based on file name and size for local sources, or plan information for other cases.

```python
>>> bucket.create_file(input_sources, remote_name, file_info)
```

--------------------------------

### List Files in Bucket

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

List files within a B2 bucket. Supports listing only the latest version of files, recursive listing, and listing files within a specific folder. The output includes file name, upload timestamp, and folder name.

```python
>>> bucket_name = 'example-mybucket-b2'
>>> bucket = b2_api.get_bucket_by_name(bucket_name)
>>> for file_version, folder_name in bucket.ls(latest_only=True):
>>>     print(file_version.file_name, file_version.upload_timestamp, folder_name)
f2.txt 1560927489000 None
som2.pdf 1554296578000 None
some.pdf 1554296579000 None
test-folder/.bzEmpty 1561005295000 test-folder/

# Recursive
>>> bucket_name = 'example-mybucket-b2'
>>> bucket = b2_api.get_bucket_by_name(bucket_name)
>>> for file_version, folder_name in bucket.ls(latest_only=True, recursive=True):
>>>     print(file_version.file_name, file_version.upload_timestamp, folder_name)
f2.txt 1560927489000 None
som2.pdf 1554296578000 None
some.pdf 1554296579000 None
test-folder/.bzEmpty 1561005295000 test-folder/
test-folder/folder_file.txt 1561005349000 None

# Within folder
>>> bucket_name = 'example-mybucket-b2'
>>> bucket = b2_api.get_bucket_by_name(bucket_name)
>>> for file_version, folder_name in bucket.ls(folder_to_list='test-folder', latest_only=True):
>>>     print(file_version.file_name, file_version.upload_timestamp, folder_name)
test-folder/.bzEmpty 1561005295000 None
test-folder/folder_file.txt 1561005349000 None

# list file versions
>>> for file_version, folder_name in bucket.ls(latest_only=False):
>>>     print(file_version.file_name, file_version.upload_timestamp, folder_name)
f2.txt 1560927489000 None
f2.txt 1560849524000 None
som2.pdf 1554296578000 None
some.pdf 1554296579000 None
```

--------------------------------

### Download File by Name

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Download a file from B2 Cloud Storage by its name within a specified bucket. The downloaded content is then saved to a local file path.

```python
>>> bucket = b2_api.get_bucket_by_name(bucket_name)
>>> b2_file_name = 'dummy_new.pdf'
>>> local_file_name = '/home/user1/b2_example/new3.pdf'
>>> downloaded_file = bucket.download_file_by_name(b2_file_name)
>>> downloaded_file.save_to(local_file_path)
```

--------------------------------

### Manual Continuation with Callback - create_file

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/advanced.md

Use a callback to store the large_file_id during the initial call, then pass it to a subsequent call to continue the upload. This is for the non-streamed version of create_file.

```python
>>> def large_file_callback(large_file):
...     # storage is not part of the interface - here only for demonstration purposes
...     storage.store({'name': remote_name, 'large_file_id': large_file.id})
>>> bucket.create_file(input_sources, remote_name, file_info, large_file_callback=large_file_callback)
# ...
>>> large_file_id = storage.query({'name': remote_name})[0]['large_file_id']
>>> bucket.create_file(input_sources, remote_name, file_info, large_file_id=large_file_id)
```

--------------------------------

### Private Interface Version Pinning

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/markup-test.rst

If you use private interfaces, pin your dependencies strictly to the exact version to avoid breaking changes.

```text
==4.5.6
```

--------------------------------

### List, Filter, and Delete Files

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Iterates through files in a bucket, applying conditional logic to delete old CSV files or download others. Requires `bucket` and `LegalHold` to be defined.

```python
>>> for file_version, folder_name in bucket.ls(latest_only=True, prefix='dir_name'):
>>>     if file_version.mod_time_millis < 1627979193913 and file_version.file_name.endswith('.csv'):
>>>         if file_version.legal_hold.is_on():
>>>             file_version = file_version.update_legal_hold(LegalHold.OFF)
>>>         file_version.delete()
>>>     else:
>>>         file_version.download().save_to(Path('/tmp/dir_name') / file_version.file_name)
```

--------------------------------

### Run tests by keyword expression

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Filter tests to run only those matching a specific keyword expression using the '-k' flag with a nox test session.

```bash
nox -s unit-3.10 -- -k keyword
```

--------------------------------

### Run Integration Tests on Specific Python Version

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Run integration tests on a specific Python version (e.g., 3.10) using `nox`. Requires setting `B2_TEST_APPLICATION_KEY` and `B2_TEST_APPLICATION_KEY_ID` environment variables.

```bash
$ export B2_TEST_APPLICATION_KEY=your_app_key
$ export B2_TEST_APPLICATION_KEY_ID=your_app_key_id
$ nox -s integration-3.10
```

--------------------------------

### Protected Interface Version Pinning

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/markup-test.rst

If you use public and protected interfaces, pin your dependencies to a more restrictive range, excluding the next minor version.

```text
>=4.5.6;<4.6.0
```

--------------------------------

### Update File Legal Hold and Retention

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Demonstrates how to update the legal hold and retention settings for a file version using both object-oriented and direct API calls.

```python
>>> file_version.update_legal_hold(LegalHold.ON)
>>> download_version.update_legal_hold(LegalHold.ON)
>>> file_version.update_retention(
        FileRetentionSetting(RetentionMode.GOVERNANCE, int(time.time() + 100)*1000))
>>> download_version.update_retention(
        FileRetentionSetting(RetentionMode.GOVERNANCE, int(time.time() + 100)*1000))
>>> # equivalent to
>>> b2_api.update_file_legal_hold(file_version.id_, file_version.file_name, LegalHold.ON)
>>> b2_api.update_file_legal_hold(download_version.id_, download_version.file_name, LegalHold.ON)
>>> b2_api.update_file_legal_hold(
        file_version.id_, file_version.file_name,
        FileRetentionSetting(RetentionMode.GOVERNANCE, int(time.time() + 100)*1000))
>>> b2_api.update_file_legal_hold(
        download_version.id_, download_version.file_name,
        FileRetentionSetting(RetentionMode.GOVERNANCE, int(time.time() + 100)*1000))
```

--------------------------------

### Synchronize Folders with DELETE Mode

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/sync.md

This snippet demonstrates synchronizing folders using the `KeepOrDeleteMode.DELETE` option. It initializes a `Synchronizer` and then calls `sync_folders` within a `SyncReport` context. This configuration will delete files from the destination if they are older in the source.

```python
>>> synchronizer = Synchronizer(
        max_workers=10,
        policies_manager=policies_manager,
        dry_run=False,
        allow_empty_source=True,
        compare_version_mode=CompareVersionMode.MODTIME,
        compare_threshold=10,
        keep_days_or_delete=KeepOrDeleteMode.DELETE,
    )
>>> with SyncReport(sys.stdout, no_progress) as reporter:
    synchronizer.sync_folders(
        source_folder=source,
        dest_folder=destination,
        now_millis=int(round(time.time() * 1000)),
        reporter=reporter,
    )
```

--------------------------------

### Synchronize Folders with REPLACE Mode

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/sync.md

This snippet shows folder synchronization with `NewerFileSyncMode.REPLACE`. When a newer file is detected in the source, it will replace the older version in the destination. This is useful for ensuring the destination always has the latest version of files.

```python
>>> synchronizer = Synchronizer(
        max_workers=10,
        policies_manager=policies_manager,
        dry_run=False,
        allow_empty_source=True,
        compare_version_mode=CompareVersionMode.MODTIME,
        compare_threshold=10,
        newer_file_mode=NewerFileSyncMode.REPLACE,
        keep_days_or_delete=KeepOrDeleteMode.DELETE,
    )
>>> with SyncReport(sys.stdout, no_progress) as reporter:
    synchronizer.sync_folders(
        source_folder=source,
        dest_folder=destination,
        now_millis=int(round(time.time() * 1000)),
        reporter=reporter,
    )
delete f2.txt (old version)
upload f2.txt
```

--------------------------------

### Run integration tests on a specific Python version

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Execute integration tests for a specific Python version, e.g., Python 3.10. Ensure B2_TEST_APPLICATION_KEY and B2_TEST_APPLICATION_KEY_ID are set.

```bash
export B2_TEST_APPLICATION_KEY=your_app_key
export B2_TEST_APPLICATION_KEY_ID=your_app_key_id
nox -s integration-3.10
```

--------------------------------

### Update File Lock Configuration

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Demonstrates how to update the legal hold status and retention settings for a file.

```APIDOC
## Update file lock configuration

This section shows how to update file lock configurations, including legal holds and retention settings.

### Method
```python
b2_api.update_file_legal_hold(file_id, file_name, LegalHold.ON)
b2_api.update_file_legal_hold(
    file_id, file_name,
    FileRetentionSetting(RetentionMode.GOVERNANCE, int(time.time() + 100)*1000))
```

### Parameters
- `file_id` (str): The ID of the file to update.
- `file_name` (str): The name of the file to update.
- `legal_hold_status` (LegalHold): The desired legal hold status (e.g., `LegalHold.ON`).
- `retention_setting` (FileRetentionSetting, optional): The retention settings for the file, including mode and duration.
```

--------------------------------

### Synchronize Folders with Encryption

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Synchronizes files between a local directory and a B2 bucket, supporting various encryption settings per bucket. Requires importing necessary modules and defining source/destination paths.

```python
>>> from b2sdk.v3 import ScanPoliciesManager
>>> from b2sdk.v3 import parse_folder
>>> from b2sdk.v3 import Synchronizer
>>> from b2sdk.v3 import SyncReport
>>> import time
>>> import sys

>>> source = '/home/user1/b2_example'
>>> destination = 'b2://example-mybucket-b2'

>>> source = parse_folder(source, b2_api)
>>> destination = parse_folder(destination, b2_api)

>>> policies_manager = ScanPoliciesManager(exclude_all_symlinks=True)

>>> synchronizer = Synchronizer(
        max_workers=10,
        policies_manager=policies_manager,
        dry_run=False,
        allow_empty_source=True,
    )

>>> no_progress = False
>>> encryption_settings_provider = BasicSyncEncryptionSettingsProvider({
        'bucket1': EncryptionSettings(mode=EncryptionMode.SSE_B2),
        'bucket2': EncryptionSettings(
                       mode=EncryptionMode.SSE_C,
                       key=EncryptionKey(secret=b'VkYp3s6v9y$B&E)H@McQfTjWmZq4t7w!', id='user-generated-key-id')
                   ),
        'bucket3': None,
    })
>>> with SyncReport(sys.stdout, no_progress) as reporter:
        synchronizer.sync_folders(
            source_folder=source,
            dest_folder=destination,
            now_millis=int(round(time.time() * 1000)),
            reporter=reporter,
            encryption_settings_provider=encryption_settings_provider,
        )
upload some.pdf
upload som2.pdf
```

--------------------------------

### Delete File using File Object

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Shows how to delete a file using either a `FileVersion` or `DownloadVersion` object.

```APIDOC
## Delete

Deletes a file using its object representation (`FileVersion` or `DownloadVersion`).

### Method
```python
file_version.delete()
download_version.delete()
```

### Equivalent Operations
```python
b2_api.delete_file_version(file_version.id_, file_version.file_name)
b2_api.delete_file_version(download_version.id_, download_version.file_name)
```
```

--------------------------------

### Obtain File Version Object by ID

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Retrieve file information using the file ID. This returns a `b2sdk.v3.FileVersion` object.

```python
>>> file_id = '4_z5485a1682662eb3e60980d10_f113f963288e711a6_d20190404_m065910_c002_v0001095_t0044'
>>> file_version = b2_api.get_file_info(file_id)
```

--------------------------------

### Check for up-to-date uv lock file

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Verify that the uv.lock file is synchronized with changes in pyproject.toml using 'uv lock --check'.

```bash
uv lock --check
```

--------------------------------

### Run Unit Tests on Specific Python Version

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/contributing.md

Execute only the unit tests on a specific Python version, like 3.10, by invoking the `unit-3.10` session with `nox`.

```bash
$ nox -s unit-3.10
```

--------------------------------

### Upload File Encrypted with SSE-C

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Upload a local file to B2 Cloud Storage using Server-Side Encryption with Customer-Provided Keys (SSE-C). Ensure the EncryptionSetting is correctly configured with the secret key and key ID.

```python
>>> local_file_path = '/home/user1/b2_example/new.pdf'
>>> b2_file_name = 'dummy_new.pdf'
>>> file_info = {'how': 'good-file'}
>>> encryption_setting = EncryptionSetting(
        mode=EncryptionMode.SSE_C,
        key=EncryptionKey(secret=b'VkYp3s6v9y$B&E)H@McQfTjWmZq4t7w!', id='user-generated-key-id'),
    )

>>> bucket = b2_api.get_bucket_by_name(bucket_name)
>>> bucket.upload_local_file(
        local_file=local_file_path,
        file_name=b2_file_name,
        file_infos=file_info,
        encryption=encryption_setting,
    )
```

--------------------------------

### Pinning b2sdk Dependency Version

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api_types.md

Use this format in requirements.txt to ensure compatibility with a specific major version of b2sdk, preventing breaking changes from future major releases.

```default
b2sdk>=1.15.0,<2.0.0
```

--------------------------------

### Download File by ID and Manage Retention

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/quick_start.md

Downloads a file using its ID, checks its content type, potentially updates retention settings, and then deletes the file. Requires `b2_api`, `Path`, `NO_RETENTION_FILE_SETTING` to be defined.

```python
>>> file_id = '4_z5485a1682662eb3e60980d10_f113f963288e711a6_d20190404_m065910_c002_v0001095_t0044'
>>> downloaded_file = b2_api.download_file_by_id(file_id)
>>> download_version = downloaded_file.download_version
>>> if download_version.content_type == 'video/mp4':
>>>     downloaded_file.save_to(Path('/tmp/dir_name') / download_version.file_name)
>>> if download_version.file_retention != NO_RETENTION_FILE_SETTING:
>>>     download_version = download_version.update_retention(
            NO_RETENTION_FILE_SETTING, bypass_governance=True)
>>> download_version.delete()
```

--------------------------------

### Run unit tests on a specific Python version

Source: https://github.com/backblaze/b2-sdk-python/blob/master/CONTRIBUTING.md

Execute only the unit tests for a specific Python version, e.g., Python 3.10, using the 'unit-3.10' nox session.

```bash
nox -s unit-3.10
```

--------------------------------

### Synchronization with Significant File Changes

Source: https://github.com/backblaze/b2-sdk-python/blob/master/doc/source/api/sync.md

Executes synchronization when a file has been modified by more than the `compare_threshold`. With `compare_threshold=10` bytes, significant changes will trigger a file replacement at the destination.

```python
>>> with SyncReport(sys.stdout, no_progress) as reporter:
        synchronizer.sync_folders(
            source_folder=source,
            dest_folder=destination,
            now_millis=int(round(time.time() * 1000)),
            reporter=reporter,
        )
upload f1.txt
```