### Install Launch File

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/rosbridge_server/CMakeLists.txt

Installs a ROS launch file for rosbridge_server. This is used to start the server within a ROS environment.

```cmake
install(FILES
  launch/rosbridge_websocket_launch.xml
  DESTINATION share/${PROJECT_NAME}/launch)
```

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

### Install Executable Scripts

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/rosbridge_server/CMakeLists.txt

Installs Python scripts as executables. These are typically the main entry points for the rosbridge server.

```cmake
install(PROGRAMS
  scripts/rosbridge_websocket.py
  scripts/rosbridge_websocket
  DESTINATION lib/${PROJECT_NAME})
```

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

### Install Python Package

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/rosbridge_server/CMakeLists.txt

Installs the Python package for rosbridge_server. Ensure ament_cmake_python is found.

```cmake
find_package(ament_cmake_python REQUIRED)

ament_python_install_package(
  ${PROJECT_NAME} PACKAGE_DIR "src/${PROJECT_NAME}")
```

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

### Example QoS Profile Object

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/ROSBRIDGE_PROTOCOL.md

Demonstrates a fully specified QoS profile for an advertise operation. Omitting the 'qos' field falls back to default settings. Individual fields within 'qos' can also be omitted to use system defaults.

```json
{
  "op": "advertise",
  "topic": "/foo",
  "type": "std_msgs/msg/String",
  "qos": {
    "history": "keep_last",
    "depth": 10,
    "reliability": "reliable",
    "durability": "volatile",
    "deadline": "infinite",
    "lifespan": 1.5
  }
}
```

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

### Check Apt Tornado Version

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/TROUBLESHOOTING.md

Query the installed version of the python-tornado package via apt. This helps in comparing with the imported version.

```bash
apt-cache show python-tornado | grep Version
```

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

### Find Local Tornado Installations

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/TROUBLESHOOTING.md

If the incorrect Tornado version persists after uninstallation, use this command to locate and manually remove any stray installations within Python's site-packages.

```bash
find /usr/local/lib/python*/*-packages/ -type d | grep '/tornado/'
```

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

### Check Imported Tornado Version

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/TROUBLESHOOTING.md

Use this command to verify the Tornado version currently imported by Python. Ensure it matches the version installed by rosdep.

```python
python -c 'import tornado; print tornado.version'
```

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

### Configure rosapi Node with All Resources

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/rosapi/README.md

Use this launch file configuration to enable all topics, services, and parameters to be returned by the rosapi node.

```xml
<launch>
  <node name="rosapi" pkg="rosapi" exec="rosapi_node">
    <param name="topics_glob" value="'[*]" />
    <param name="services_glob" value="'[*]" />
    <param name="params_glob" value="'[*]" />
  </node>
</launch>
```

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

### Configure rosapi Node with Specific Topics

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/rosapi/README.md

This launch file configuration demonstrates how to enable only specific topics, such as \/rosout and camera-related topics, for the rosapi node.

```xml
<launch>
  <node name="rosapi" pkg="rosapi" exec="rosapi_node">
    <param name="topics_glob" value="'[/rosout, /camera/rgb/*]'" />
  </node>
</launch>
```

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

### Configure Launch Tests

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/rosbridge_server/CMakeLists.txt

Sets up launch tests for various WebSocket scenarios. Each test is run with both SingleThreadedExecutor and EventsExecutor.

```cmake
set(TEST_FILES
  test/websocket/advertise_action.test.py
  test/websocket/advertise_action_feedback.test.py
  test/websocket/advertise_publish.test.py
  test/websocket/advertise_service.test.py
  test/websocket/call_service.test.py
  test/websocket/send_action_goal.test.py
  test/websocket/smoke.test.py
  test/websocket/transient_local_publisher.test.py
  test/websocket/best_effort_publisher.test.py
  test/websocket/multiple_subscribers_raw.test.py
)

foreach(TEST_FILE ${TEST_FILES})
  # Extract base name for test naming
  get_filename_component(TEST_NAME ${TEST_FILE} NAME_WE)

  # Run with SingleThreadedExecutor (default)
  add_launch_test(${TEST_FILE}
    TARGET ${TEST_NAME}_singlethreaded
    ARGS "use_events_executor:=false"
  )

  # Run with EventsExecutor
  add_launch_test(${TEST_FILE}
    TARGET ${TEST_NAME}_events
    ARGS "use_events_executor:=true"
  )
endforeach()
```

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

### Advertise Topic with QoS and Unadvertise

Source: https://context7.com/robotwebtools/rosbridge_suite/llms.txt

Register a ROS publisher on a topic using the 'advertise' operation. Optional 'qos' settings can override defaults. 'unadvertise' removes specific or all advertisements for a topic.

```json
// Advertise with explicit QoS
{
  "op": "advertise",
  "id": "adv-1",
  "topic": "/cmd_vel",
  "type": "geometry_msgs/msg/Twist",
  "qos": {
    "history":     "keep_last",
    "depth":       10,
    "reliability": "reliable",
    "durability":  "volatile"
  }
}
```

```json
// Unadvertise (remove this specific advertisement only)
{
  "op": "unadvertise",
  "id": "adv-1",
  "topic": "/cmd_vel"
}
```

```json
// Unadvertise all advertisements for the topic by this client
{ "op": "unadvertise", "topic": "/cmd_vel" }
```

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

### Uninstall Pip Tornado

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/TROUBLESHOOTING.md

If a conflicting Tornado version was installed via pip, use this command to uninstall it. This is a common step when versions do not match.

```bash
pip uninstall tornado
```

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

### rosapi Services: Get Parameter

Source: https://context7.com/robotwebtools/rosbridge_suite/llms.txt

Retrieve the value of a ROS parameter using '/rosapi/get_param'. Specify the 'name' of the parameter and an optional 'default' value.

```json
// Get a ROS parameter value
{
  "op": "call_service",
  "id": "q5",
  "service": "/rosapi/get_param",
  "args": { "name": "/my_robot_node.max_speed", "default": "1.0" }
}
// Response: { "value": "0.8" }
```

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

### Launch rosbridge WebSocket Server

Source: https://context7.com/robotwebtools/rosbridge_suite/llms.txt

Launches the rosbridge WebSocket server and the companion rosapi node. Configuration can be provided via arguments.

```APIDOC
## Launch rosbridge WebSocket Server

Start the WebSocket server (default port 9090) and the companion rosapi node using the supplied launch file. The server and `rosapi` share the same glob-filter parameters so access control is configured in one place.

```xml
<!-- rosbridge_websocket_launch.xml – minimal launch -->
<launch>
  <arg name="port"          default="9090" />
  <arg name="topics_glob"   default="" />   <!-- e.g. "[/rosout, /camera/*]" -->
  <arg name="services_glob" default="" />
  <arg name="params_glob"   default="" />

  <node name="rosbridge_websocket"
        pkg="rosbridge_server"
        exec="rosbridge_websocket"
        output="screen">
    <param name="port"          value="$(var port)"/>
    <param name="topics_glob"   value="$(var topics_glob)"/>
    <param name="services_glob" value="$(var services_glob)"/>
    <param name="params_glob"   value="$(var params_glob)"/>
  </node>

  <node name="rosapi" pkg="rosapi" exec="rosapi_node">
    <param name="topics_glob"   value="$(var topics_glob)"/>
    <param name="services_glob" value="$(var services_glob)"/>
    <param name="params_glob"   value="$(var params_glob)"/>
  </node>
</launch>
```

```bash
# From the command line
ros2 launch rosbridge_server rosbridge_websocket_launch.xml port:=9090
```
```

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

### rosapi Services: List Nodes

Source: https://context7.com/robotwebtools/rosbridge_suite/llms.txt

Call '/rosapi/nodes' to get a list of all active nodes in the ROS graph. The response contains a 'nodes' array with node names.

```json
// List all nodes
{
  "op": "call_service",
  "id": "q3",
  "service": "/rosapi/nodes"
}
// Response: { "nodes": ["/my_robot_node", "/rosbridge_websocket", ...] }
```

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

### Minimal and Correlated rosbridge Messages

Source: https://context7.com/robotwebtools/rosbridge_suite/llms.txt

Examples of minimal and valid rosbridge messages. The 'id' field is used to correlate requests with their responses, spanning the lifetime of an interaction.

```json
// Minimal valid rosbridge message
{ "op": "subscribe", "topic": "/chatter" }
```

```json
// With correlation ID
{
  "op": "call_service",
  "id": "req-42",
  "service": "/rosapi/topics",
  "args": {}
}
```

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

### Launch rosbridge WebSocket Server and rosapi

Source: https://context7.com/robotwebtools/rosbridge_suite/llms.txt

Launch the rosbridge WebSocket server and the companion rosapi node using a provided XML launch file. Configuration for port and glob filters is done via ROS 2 parameters.

```xml
<launch>
  <arg name="port"          default="9090" />
  <arg name="topics_glob"   default="" />   <!-- e.g. "[/rosout, /camera/*]" -->
  <arg name="services_glob" default="" />
  <arg name="params_glob"   default="" />

  <node name="rosbridge_websocket"
        pkg="rosbridge_server"
        exec="rosbridge_websocket"
        output="screen">
    <param name="port"          value="$(var port)"/>
    <param name="topics_glob"   value="$(var topics_glob)"/>
    <param name="services_glob" value="$(var services_glob)"/>
    <param name="params_glob"   value="$(var params_glob)"/>
  </node>

  <node name="rosapi" pkg="rosapi" exec="rosapi_node">
    <param name="topics_glob"   value="$(var topics_glob)"/>
    <param name="services_glob" value="$(var services_glob)"/>
    <param name="params_glob"   value="$(var params_glob)"/>
  </node>
</launch>
```

```bash
# From the command line
ros2 launch rosbridge_server rosbridge_websocket_launch.xml port:=9090
```

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

### rosapi Services: Get Node Details

Source: https://context7.com/robotwebtools/rosbridge_suite/llms.txt

Obtain details about a specific node, including its publishers, subscribers, and services, by calling '/rosapi/node_details'. Provide the 'node' name in 'args'.

```json
// Get details for a node (its publishers, subscribers, and services)
{
  "op": "call_service",
  "id": "q4",
  "service": "/rosapi/node_details",
  "args": { "node": "/my_robot_node" }
}
// Response: { "subscribing": ["/scan"], "publishing": ["/cmd_vel"], "services": [] }
```

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

### Advertise Topic

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/ROSBRIDGE_PROTOCOL.md

Registers the client as a publisher on a specified topic. This operation allows the server to track publishers and establish the topic with the correct type if it doesn't exist. Deprecated fields `latch` and `queue_size` are superseded by the `qos` object.

```APIDOC
## POST /advertise

### Description
Registers the client as a publisher on a topic. This allows the server to track which clients are publishing on which topics, and to establish the topic with the correct type if it does not already exist.

### Method
POST

### Endpoint
/advertise

### Parameters
#### Request Body
- **op** (string) - required - Must be "advertise"
- **id** (string) - optional - An ID to associate with this advertisement. Useful when multiple components advertise the same topic so that each can be unadvertised independently.
- **topic** (string) - required - The name of the topic to advertise.
- **type** (string) - required - The type of the topic to advertise.
- **qos** (object) - optional - QoS profile for the publisher. See section 4.2.1 for the object format and available fields. If omitted, the default rosbridge QoS is used (see section 4.2.2). If present, `latch` and `queue_size` are ignored.
- **latch** (boolean) - optional - Deprecated. Use `qos.durability` instead. Whether to latch the last message published on this topic.
- **queue_size** (integer) - optional - Deprecated. Use `qos.depth` instead. The QoS depth policy.

### Request Example
```json
{
  "op": "advertise",
  "topic": "/foo",
  "type": "std_msgs/msg/String",
  "qos": {
    "history": "keep_last",
    "depth": 10,
    "reliability": "reliable",
    "durability": "volatile",
    "deadline": "infinite",
    "lifespan": 1.5
  }
}
```

### Response
#### Success Response (200)
- **op** (string) - Confirmation of the operation, e.g., "advertised"
- **id** (string) - The ID associated with the advertisement, if provided.

#### Response Example
```json
{
  "op": "advertised",
  "id": "my_advertisement_id"
}
```

**Note:** The operation fails if the topic already exists with a different type or if the specified type cannot be resolved. Only the first advertisement determines the QoS settings for a topic.
```

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

### rosapi Services: Get Topic Type

Source: https://context7.com/robotwebtools/rosbridge_suite/llms.txt

Retrieve the message type of a specific topic by calling '/rosapi/topic_type' with the topic name. The 'args' field should contain the 'topic' key.

```json
// Get type of a specific topic
{
  "op": "call_service",
  "id": "q2",
  "service": "/rosapi/topic_type",
  "args": { "topic": "/scan" }
}
// Response: { "type": "sensor_msgs/msg/LaserScan" }
```

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

### Configure unregister_timeout in rosbridge_websocket

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/rosbridge_server/CHANGELOG.rst

Make the unregister_timeout configurable by passing an argument in a launch file. This allows adjustment of the delay for mitigating client unregistration issues.

```xml
<launch>
<include file="$(find rosbridge_server)/launch/rosbridge_websocket.launch">
<arg name="unregister_timeout" value="5.0"/>
</include>
</launch>
```

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

### Base64 Encoding of Byte Arrays

Source: https://github.com/robotwebtools/rosbridge_suite/blob/ros2/ROSBRIDGE_PROTOCOL.md

Byte arrays (uint8[] or char[]) are base64 encoded when sent by the rosbridge server to reduce message size. This example shows how uint8 arrays are represented as base64 strings.

```json
{ "data1": "AAAAAA==", "data2": "/////w==" }
```