### HTTP GET and POST Examples

Source: https://docs.lsfusion.org/v6/EXTERNAL_operator

Demonstrates fetching data from a URL using HTTP GET and sending JSON data with HTTP POST. Note that braces in JSON parameters are escaped.

```lsfusion
testExportFile = DATA FILE ();  

externalHTTP()  {
    EXTERNAL HTTP GET 'https://www.cs.cmu.edu/~chuck/lennapg/len_std.jpg' TO exportFile;  
    open(exportFile());  
    // braces are escaped as they are used in internationalization  
    EXTERNAL HTTP 'http://tryonline.lsfusion.org/exec?action=getExamples'   
             PARAMS JSONFILE('{"mode"=1,"locale"="en"}') TO exportFile;   
    IMPORT FROM exportFile() FIELDS () TEXT caption, TEXT code DO  
        MESSAGE 'Example : ' + caption + ', code : ' + code;

    // passes the second and third parameters to BODY url-encoded  
    EXTERNAL HTTP 'http://tryonline.lsfusion.org/exec?action=doSomething&someprm=$1'   
             BODYURL 'otherprm=$2&andonemore=$3' PARAMS 1,2,'3';   
}
```

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

### Install lsFusion 6 Server & Client on Ubuntu/Debian

Source: https://docs.lsfusion.org/Execution_auto

Use this command to install lsFusion 6 Server and Client on Ubuntu 18+ or Debian 9+ systems. It sources a script that handles OpenJDK, PostgreSQL, and Tomcat setup.

```bash
source <(curl -s https://download.lsfusion.org/apt/install-lsfusion6)
```

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

### Example conf/settings.properties for lsFusion

Source: https://docs.lsfusion.org/v6/Launch_parameters

This example shows how to configure database and RMI settings in the conf/settings.properties file. Ensure the file is placed in the application server's startup folder.

```properties
db.server=localhost
db.name=lsfusion
db.user=postgres
db.password=pswrd

rmi.port=7652
```

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

### CHANGEKEY Example with Mode Options

Source: https://docs.lsfusion.org/v6/Action_options

Example demonstrating how to set a keyboard shortcut with specific execution conditions. This example sets Ctrl+Shift+A as the shortcut, with a priority of 100, and specifies that it should only execute when in a dialog window and when the action is currently being edited.

```plaintext
CHANGEKEY "Ctrl+Shift+A;(priority=100;dialog=only;editing=only)"
```

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

### Install lsFusion 6 Server & Client on RHEL/CentOS/Fedora

Source: https://docs.lsfusion.org/Execution_auto

Use this command to install lsFusion 6 Server and Client on RHEL 8+, CentOS 8+, or Fedora 35+ systems. It sources a script that handles OpenJDK, PostgreSQL, and Tomcat setup.

```bash
source <(curl -s https://download.lsfusion.org/dnf/install-lsfusion6)
```

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

### SQL Export and Import Example

Source: https://docs.lsfusion.org/v6/EXTERNAL_operator

Shows how to export data to a SQL database and then import data back from it. This example retrieves product barcodes and then updates their prices.

```lsfusion
externalSQL ()  {
    // getting all barcodes of products with the name meat  
    EXPORT TABLE FROM bc=barcode(Article a) WHERE name(a) LIKE '%Meat%';  
    // reading prices for read barcodes   
    EXTERNAL SQL 'jdbc:mysql://$1/test?user=root&password='   
             EXEC 'select price AS pc, articles.barcode AS brc from $2 x JOIN articles ON x.bc=articles.barcode'   
             PARAMS 'localhost', exportFile()   
             TO exportFile;   

    // writing prices for all products with received barcodes  
    LOCAL price = INTEGER (INTEGER);  
    LOCAL barcode = STRING[30] (INTEGER);  
    IMPORT FROM exportFile() TO price=pc,barcode=brc;  
    FOR barcode(Article a) = barcode(INTEGER i) DO  
        price(a) <- price(i);  
}
```

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

### Start LSFusion Application Server on Linux

Source: https://docs.lsfusion.org/Execution_manual

Command to start the LSFusion application server as a service on Linux. Ensure the CLASSPATH includes the server JAR file.

```bash
java -cp ".:lsfusion-server-6.2.jar" lsfusion.server.logics.BusinessLogicsBootstrap  
```

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

### Start LSFusion Application Server on Windows

Source: https://docs.lsfusion.org/Execution_manual

Command to start the LSFusion application server on Windows. Ensure the CLASSPATH includes the server JAR file.

```cmd
java -cp ".;lsfusion-server-6.2.jar" lsfusion.server.logics.BusinessLogicsBootstrap  
```

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

### Static Object ID Examples in lsFusion

Source: https://docs.lsfusion.org/IDs

Examples demonstrating how to reference static objects within classes.

```lsfusion
Direction.north
```

```lsfusion
System.FormResult.ok
```

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

### Start lsFusion 6 Server (Windows Command Line)

Source: https://docs.lsfusion.org/Execution_auto

Command to start the lsFusion 6 Application Server service on Windows.

```cmd
$INSTALL_DIR/Server/bin/lsfusion6_server.exe //ES//lsfusion6_server
```

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

### Install Certbot and Generate Certificate

Source: https://docs.lsfusion.org/Execution_auto

Install Certbot and use it to obtain a standalone SSL certificate for your domain.

```bash
apt install certbot
```

```bash
certbot certonly --standalone -d myaddress.com
```

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

### HTTP GET Request and File Import

Source: https://docs.lsfusion.org/v6/Access_to_an_external_system_EXTERNAL

Demonstrates making an HTTP GET request to fetch a file and then opening it. It also shows how to make an HTTP request with JSON parameters and import data from the response.

```lsfusion
testExportFile = DATA FILE ();

externalHTTP() {
    EXTERNAL HTTP GET 'https://www.cs.cmu.edu/~chuck/lennapg/len_std.jpg' TO exportFile;
    open(exportFile());

    // braces are escaped as they are used in internationalization
    EXTERNAL HTTP 'http://tryonline.lsfusion.org/exec?action=getExamples'
             PARAMS JSONFILE('{"mode"=1,"locale"="en"}')
             TO exportFile;
    IMPORT FROM exportFile() FIELDS () TEXT caption, TEXT code DO
        MESSAGE 'Example : ' + caption + ', code : ' + code;

    // passes the second and third parameters to BODY url-encoded
    EXTERNAL HTTP 'http://tryonline.lsfusion.org/exec?action=doSomething&someprm=$1'
             BODYURL 'otherprm=$2&andonemore=$3'
             PARAMS 1,2,'3';
}
```

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

### Install Application Server (lsFusion 6 Server) on Ubuntu/Debian

Source: https://docs.lsfusion.org/Execution_auto

Use this command to install the lsFusion 6 Application Server, including OpenJDK, on Ubuntu 18 or Debian 9.

```bash
source <(curl -s https://download.lsfusion.org/apt/install-lsfusion6-server)
```

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

### Aggregate function examples

Source: https://docs.lsfusion.org/Set_operations

Demonstrates the usage of GROUP SUM with a finite set and potential errors with infinite sets. Includes examples of successful execution and platform errors.

```lsfusion
CLASS A;
d = DATA INTEGER (A);
  
f (b) = GROUP SUM 1 IF d(a) < b;
messageF  { MESSAGE f(5); } // will be executed successfully  
  
g = GROUP SUM f(b);
messageG  { MESSAGE g(); } // f(b) is not NULL for infinite set b, the platform will throw an error  
  
FORM f  
    OBJECTS d=DATE  
;
  
printFWithD { PRINT f OBJECTS d=currentDate(); } // will be executed successfully  
  
// there is no filter for dates, and d IS DATE is not NULL for an infinite set d, the platform will throw an error  
printFWithoutD { PRINT f; }   

```

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

### Install Database Server (PostgreSQL) on Ubuntu/Debian

Source: https://docs.lsfusion.org/Execution_auto

Use this command to install the lsFusion 6 Database Server (PostgreSQL) on Ubuntu 18+ or Debian 9+.

```bash
source <(curl -s https://download.lsfusion.org/apt/install-lsfusion6-db)
```

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

### CHANGEMOUSE Example with SHOW Option

Source: https://docs.lsfusion.org/v6/Action_options

Example of setting a double-click mouse event as a trigger for an action, with the condition that the mouse click should be displayed in the action header.

```plaintext
CHANGEMOUSE DBLCLK SHOW
```

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

### Example Pivot Table Configuration

Source: https://docs.lsfusion.org/v6/Pivot_block

A complete example demonstrating the usage of the PIVOT block to configure columns, rows, measures, and options for a pivot table within a FORM statement.

```lsfusion
FORM PivotTest   
    OBJECTS s = Store  
    PROPERTIES(s) name, storeSizeCode, storeSizeName, storeSizeFullName  
    PIVOT s 'Bar Chart' NOSETTINGS MAX  
        ROWS (name(s), MEASURES(s)) COLUMNS storeSizeName(s), storeSizeFullName(s) MEASURES storeSizeCode(s)      
;  
```

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

### Install Web Server (lsFusion 6 Client) on Ubuntu/Debian

Source: https://docs.lsfusion.org/Execution_auto

Use this command to install the lsFusion 6 Web Server (Client), including Tomcat 9.0.104, on Ubuntu 18 or Debian 9.

```bash
source <(curl -s https://download.lsfusion.org/apt/install-lsfusion6-client)
```

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

### Example lsFusion Query

Source: https://docs.lsfusion.org/How-to_Frontend

This is an example of a script that can be passed to the select function to retrieve specific game data from the lsFusion backend. The EXPORT FROM operator is implicitly handled by the select function.

```javascript
select("date(Game g), hostTeamName(g), hostGoals(g), guestGoals(g), guestTeamName(g), resultName(g)")  
```

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

### ACTION Statement Examples

Source: https://docs.lsfusion.org/v6/ACTION_statement

Illustrates basic declarations of actions using the ACTION statement. The first example shows a simple action with a message, while the second demonstrates an action with a caption and an abstract parameter.

```lsfusion
showMessage  { MESSAGE 'Hello World!'; } 				// action declaration
```

```lsfusion
loadImage 'Upload image'  ABSTRACT ( Item);
```

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

### Example Java Startup Option

Source: https://docs.lsfusion.org/Launch_parameters

Set the `logics.topModule` parameter directly in Java startup options using the `-D` prefix.

```bash
-Dlogics.topModule=FFF
```

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

### Example Module Header with Class and Property Definition

Source: https://docs.lsfusion.org/v6/Module_header

Illustrates a complete module header with module name, dependencies, namespace, and subsequent class and property definitions.

```lsfusion
MODULE EmployeeExample; 
  
REQUIRE System, Utils; 
NAMESPACE Employee;
  
CLASS Employee 'Employee';
CLASS Position 'Position'; 
  
employeePosition(employee) = DATA Position (Employee);

```

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

### SCHEDULE PERIOD Statement Example

Source: https://docs.lsfusion.org/NAVIGATOR_statement

Demonstrates how to schedule an action to run periodically, with an option to fix the period count from the action's start time.

```plaintext
SCHEDULE PERIOD intPeriod [FIXED] action;
```

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

### Example Module Header

Source: https://docs.lsfusion.org/Module_header

Illustrates a complete module header with module name, dependencies, namespace, and class/property definitions.

```lsfusion
MODULE EmployeeExample; 
  
REQUIRE System, Utils; 
NAMESPACE Employee; 
  
CLASS Employee 'Employee'; 
CLASS Position 'Position'; 
  
employeePosition(employee) = DATA Position (Employee);

```

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

### Define Book and Tag Classes

Source: https://docs.lsfusion.org/v6/How-to_GROUP_CONCAT

Defines the 'Book' and 'Tag' classes with their respective properties and the 'in' relationship between them. This setup is required for the subsequent GROUP CONCAT example.

```lsfusion
CLASS Book 'Book';
CLASS Tag 'Tag';
name 'Name' = DATA ISTRING[10] (Tag);

in 'On' = DATA BOOLEAN (Tag, Book);
```

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

### Simple ID Examples in lsFusion

Source: https://docs.lsfusion.org/IDs

Simple IDs are basic identifiers consisting of letters, digits, and underscores, starting with a letter. They are used for naming system elements and parameters.

```lsfusion
name
```

```lsfusion
value_id13
```

```lsfusion
bankAccount
```

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

### Basic NEWSESSION Example

Source: https://docs.lsfusion.org/v6/NEWSESSION_operator

Demonstrates creating a new Currency object in a new session and applying the changes. The object will be present in the database after the session closes.

```lsfusion
testNewSession ()  {
    NEWSESSION { 
        NEW c = Currency {
            name(c) <- 'USD';
            code(c) <- 866;
        }
        APPLY;
    }
    // here a new object of class Currency is already in the database

    LOCAL local = BPSTRING[10] (Currency);
    local(Currency c) <- 'Local';
    NEWSESSION { 
        MESSAGE (GROUP SUM 1 IF local(Currency c) == 'Local'); // will return NULL
    }
    NEWSESSION NESTED (local) {
        // will return the number of objects of class Currency
        MESSAGE (GROUP SUM 1 IF local(Currency c) == 'Local'); 
    }

    NEWSESSION {
        NEW s = Sku {
            id(s) <- 1234;
            name(s) <- 'New Sku';
            SHOW sku OBJECTS s = s;
        }
    }

}

```

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

### Define Book and Category Classes

Source: https://docs.lsfusion.org/How-to_IF_CASE

Defines the data structures for Book and Category, including their properties like name, category, and price. This setup is required for the subsequent examples.

```lsfusion
CLASS Book 'Book';  
name 'Name' = DATA ISTRING[50] (Book);  
  
CLASS Category 'Category' {
    novel 'Novel',
    thriller 'Thriller',
    fiction 'Fiction'
}

category 'Category' = DATA Category (Book);
price 'Price' = DATA NUMERIC[14,2] (Book);
```

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

### Start/Stop Application Server (lsfusion6_client)

Source: https://docs.lsfusion.org/Execution_auto

Use these commands to start or stop the LSFusion application server using its client executable.

```bash
$INSTALL_DIR/Client/bin/lsfusion6_client.exe //SS//lsfusion6_client
```

```bash
$INSTALL_DIR/Client/bin/lsfusion6_client.exe //ES//lsfusion6_client
```

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

### Number Order Lines with PARTITION SUM

Source: https://docs.lsfusion.org/How-to_PARTITION

Use PARTITION SUM to number order lines sequentially starting from 1 as they are added. This example sorts by the internal ID of lines within an order.

```lsfusion
CLASS Order 'Order';
CLASS OrderDetail 'Order line';

order 'Order' = DATA Order (OrderDetail) NONULL DELETE;

```

```lsfusion
index 'Line number' (OrderDetail d) = PARTITION SUM 1 ORDER d BY order(d) CHARWIDTH 4;

```

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

### Define Book and Category Data Structures

Source: https://docs.lsfusion.org/How-to_Reports

Defines the data model for categories and books, including relationships and a method to get the category name for a book. This setup is necessary before creating report forms.

```lsfusion
NAMESPACE Sample;  
  
CLASS Category 'Category';  
name 'Name' = DATA ISTRING[50] (Category) IN id;  
  
CLASS Book 'Book';  
name 'Name' = DATA ISTRING[100] (Book) IN id;  
  
category 'Category' = DATA Category (Book) AUTOSET;  
nameCategory 'Category' (Book b) = name(category(b)) IN id;  
  
countBooks 'Number of books' (Category c) = GROUP SUM 1 BY category(Book b);  

FORM books 'Books'  
    OBJECTS b = Book  
    PROPERTIES(b) READONLY name, nameCategory  
    PROPERTIES(b) NEWSESSION NEW, EDIT, DELETE  
;  
  
NAVIGATOR {
    NEW books;
}

```

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

### Show Form Example

Source: https://docs.lsfusion.org/In_an_interactive_view_SHOW_DIALOG

Demonstrates opening a form with specified date ranges and within a new session. The form is displayed as a floating window.

```lsfusion
date = DATA DATE (Order);
FORM showForm
    OBJECTS dateFrom = DATE, dateTo = DATE PANEL
    PROPERTIES VALUE(dateFrom), VALUE(dateTo)
  
    OBJECTS o = Order
    FILTERS date(o) >= dateFrom, date(o) <= dateTo
;
  
testShow ()  {
    SHOW showForm OBJECTS dateFrom = 2010_01_01, dateTo = 2010_12_31;

    NEWSESSION {
        NEW s = Sku {
            SHOW sku OBJECTS s = s FLOAT;
        }
    }
}
```

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

### Example XML Output

Source: https://docs.lsfusion.org/How-to_Data_export

This is an example of the XML structure generated from the defined form.

```xml
<Order timeStamp="13.11.18 12:28:58">
   <Info>
      <date>13.11.18</date>
      <number>12</number>
      <Customer>
         <name>Customer2</name>
         <address>Address2</address>
      </Customer>
   </Info>
   <Specification count="2">
      <Detail>
         <nameBook>Book2</nameBook>
         <quantity>1</quantity>
         <price currency="USD">3.99</price>
      </Detail>
      <Detail>
         <nameBook>Book1</nameBook>
         <quantity>2</quantity>
         <price currency="EUR">4.99</price>
      </Detail>
   </Specification>
</Order>
```

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

### SHOW Operator Example with Object Initialization and Nested Session

Source: https://docs.lsfusion.org/SHOW_operator

Demonstrates opening a form with initial object values, a nested session, and an inline initialization action.

```lsfusion
date = DATA DATE (Order);
FORM showForm
    OBJECTS dateFrom = DATE, dateTo = DATE PANEL
    PROPERTIES VALUE(dateFrom), VALUE(dateTo)

    OBJECTS o = Order
    FILTERS date(o) >= dateFrom, date(o) <= dateTo
;

testShow () {
    SHOW showForm OBJECTS dateFrom = 2010_01_01, dateTo = 2010_12_31 { MESSAGE 'On init'; };

    NEWSESSION {
        NEW s = Sku {
            SHOW sku OBJECTS s = s FLOAT;
        }
    }
}
```

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

### EMAIL Operator Examples

Source: https://docs.lsfusion.org/EMAIL_operator

Illustrative examples of how to use the EMAIL operator in different scenarios.

```APIDOC
## EMAIL Operator Examples

### Example 1: Sending a login reminder email
```
FORM remindUserPass  
    OBJECTS u=CustomUser PANEL  
    PROPERTIES(u) READONLY login, name[Contact]  
;

emailUserPassUser 'Login reminder' (CustomUser user)  {
    LOCAL bodyFile = FILE ();
    PRINT remindUserPass OBJECTS u = user HTML TO bodyFile;
    EMAIL
        SUBJECT 'Login reminder'
        TO email(user)
        BODY bodyFile()
        NOWAIT
    ;
}
```

### Example 2: Sending a simple email with a body from a file
```
justSendEmail 'Send letter' ()  {
    stringToFile('<font color=#FF0000 size=+3>big red text</font>');
    EMAIL
        FROM 'luxsoft@adsl.by'
        SUBJECT 'Letter subject'
        TO 'xxx@tut.by'
        BODY resultFile()
    ;
}
```
```

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

### Define a Module with Dependencies and Classes

Source: https://docs.lsfusion.org/v6/Modules

This example demonstrates how to define a module named 'EmployeeExample', specify its dependencies on 'System' and 'Utils' modules, set its namespace to 'Employee', and declare two classes, 'Employee' and 'Position', along with a property 'employeePosition'.

```lsfusion
MODULE EmployeeExample;	 	 	// Defining the module name  
  
REQUIRE System, Utils; 	 	// Listing the modules that the Employee module depends on  
NAMESPACE Employee;	 	 	// Setting the namespace  
  
CLASS Employee 'Employee';	// Creating a class  
CLASS Position 'Position'; // Creating another class  
  
employeePosition(employee) = DATA Position (Employee); // Creating property  

```

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

### Enable API via Java startup parameters

Source: https://docs.lsfusion.org/MCP_server

Use Java startup parameters to set the `enableAPI` system property. A value of `1` permits authenticated API access.

```bash
-Dsettings.enableAPI=1
```

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

### Composite ID Examples in lsFusion

Source: https://docs.lsfusion.org/IDs

Examples of composite IDs, including those with and without a specified namespace.

```lsfusion
System.name
```

```lsfusion
Sale.Document
```

```lsfusion
name
```

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

### Implement Abstract LIST Action

Source: https://docs.lsfusion.org/v6/ACTION_plus_statement

Demonstrates implementing an abstract LIST action 'onStarted' with two separate implementations. Both implementations are executed sequentially.

```lsfusion
onStarted  ABSTRACT LIST ( );
onStarted () + {
    name(Sku s) <- '1';
}
onStarted () + {
    name(Sku s) <- '2';
}
// first, the 1st action is executed, then the 2nd action

```

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

### Example: Copying Order Properties with {...}

Source: https://docs.lsfusion.org/Braces_operator

Demonstrates how to use the {...} operator to create a new action that sequentially copies currency and customer data from an old order to a new one. Local properties are scoped to the operator.

```lsfusion
CLASS Currency;
name = DATA STRING[30] (Currency);
code = DATA INTEGER (Currency);

CLASS Order;
currency = DATA Currency (Order);
customer = DATA STRING[100] (Order);
copy 'Copy' (Order old) {
    NEW new = Order { // an action is created that consists of the sequential execution of two actions
        currency(new) <- currency(old); // a semicolon is put after each statement
        customer(new) <- customer(old);
    } // there is no semicolon in this line, because the operator ends in }
}
```

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

### Typed Parameter Examples in lsFusion

Source: https://docs.lsfusion.org/IDs

Examples of typed parameters, showing usage with and without explicit class IDs.

```lsfusion
user
```

```lsfusion
User user
```

```lsfusion
System.User user
```

```lsfusion
INTEGER count
```

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

### Create a basic TABLE statement

Source: https://docs.lsfusion.org/TABLE_statement

This example demonstrates the basic syntax for creating a table named 'book' with a single key class 'Book'.

```lsfusion
TABLE book (Book);
```

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

### Property/Action Canonical Name Examples

Source: https://docs.lsfusion.org/v6/Naming

Provides specific examples of canonical names for properties and actions with different parameter types.

```plaintext
Item.gender[Item.Article]
Date.between[DATE,DATE,DATE]
Document.addHeader[Document.Document,STRING]
Math.sum[?,?]
```

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

### Using Dialogs for Selection and Input

Source: https://docs.lsfusion.org/Interactive_view

Demonstrates how to use dialogs for selecting a SKU and for changing a SKU associated with an order detail. It includes examples of both input and change modes for dialogs.

```lsfusion
FORM selectSku  
    OBJECTS s = Sku  
    PROPERTIES(s) id  
;
  
testDialog  {
    DIALOG selectSku OBJECTS s INPUT DO {
        MESSAGE 'Selected sku : ' + id(s);
    }
}
  
sku = DATA Sku (OrderDetail);

idSku (OrderDetail d) = id(sku(d));

changeSku (OrderDetail d)  {
    DIALOG selectSku OBJECTS s = sku(d) CHANGE;

    //equivalent to the first option
    DIALOG selectSku OBJECTS s = sku(d) INPUT NULL CONSTRAINTFILTER DO {
        sku(d) <- s;
    }
}


```

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

### Property or Action on a Form ID Examples in lsFusion

Source: https://docs.lsfusion.org/IDs

Examples of IDs used for properties or actions directly associated with a form.

```lsfusion
barcodeSku.amount(b)
```

```lsfusion
Item.items.name(i)
```

```lsfusion
Consignment.dashboard.date
```

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

### Example JSON Payload for City Creation

Source: https://docs.lsfusion.org/v6/How-to_Interaction_via_HTTP_protocol

This is an example of the JSON payload that is generated and sent in the HTTP request body for creating a city.

```json
{"countryId":"123","name":"San Francisco"}

```

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

### Expand Up Example

Source: https://docs.lsfusion.org/v6/EXPAND_operator

This example shows how to expand elements upwards, including ancestors. It targets a specific navigator element by its canonical name.

```javascript
FORM expandCollapseTest  
    TREE elements e = NavigatorElement PARENT parent(e)  
    PROPERTIES(e) READONLY BACKGROUND NOT e IS NavigatorFolder VALUE, canonicalName, caption  
;

expandUp {
    EXPAND UP expandCollapseTest.e OBJECTS e = navigatorElementCanonicalName('System.administration');
}

EXTEND FORM expandCollapseTest
    PROPERTIES() expandUp
;
```

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

### Write File Action Example

Source: https://docs.lsfusion.org/Write_file_WRITE

Demonstrates how to use the WRITE operator to save a file to different destinations. Supports appending and writing from the client.

```lsfusion
loadAndWrite ()  {
    INPUT f = FILE DO {
        WRITE f TO 'file:///home/user/loadedfile.csv' APPEND;
        WRITE CLIENT f TO '/home/user/loadedfile.txt';
        WRITE CLIENT DIALOG f TO 'loadedfile';
    }
}
```

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

### Create a full TABLE statement

Source: https://docs.lsfusion.org/TABLE_statement

This example demonstrates creating a 'full' table named 'sku' with 'Sku' as its key class. A 'full' table includes all objects belonging to the key classes.

```lsfusion
TABLE sku (Sku) FULL;
```

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

### Expand Down Example

Source: https://docs.lsfusion.org/v6/EXPAND_operator

This example demonstrates expanding elements downwards in the object tree. It targets a specific navigator element by its canonical name.

```javascript
FORM expandCollapseTest  
    TREE elements e = NavigatorElement PARENT parent(e)  
    PROPERTIES(e) READONLY BACKGROUND NOT e IS NavigatorFolder VALUE, canonicalName, caption  
;

expandDown {
    EXPAND DOWN expandCollapseTest.e OBJECTS e = navigatorElementCanonicalName('System.administration');
}

EXTEND FORM expandCollapseTest
    PROPERTIES() expandDown
;
```

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

### Define Report Hierarchy Example

Source: https://docs.lsfusion.org/Print_view

Example of defining a form structure with object groups and properties, illustrating potential report hierarchy.

```lsfusion
FORM myForm 'myForm' 
    OBJECTS A, B SUBREPORT, C, D, E 
    PROPERTIES f(B, C), g(A, C) 
    FILTERS c(E) = C, h(B, D) 
;  
```

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

### Define and Execute Sequential Actions

Source: https://docs.lsfusion.org/Sequence

Demonstrates defining classes and then creating an action that copies data sequentially. It also shows how to load default currencies and run a sequence of these loads.

```lsfusion
CLASS Currency;
name = DATA STRING[30] (Currency);
code = DATA INTEGER (Currency);

CLASS Order;
currency = DATA Currency (Order);
customer = DATA STRING[100] (Order);
copy 'Copy' (Order old) {
    // an action is created that consists of the sequential execution of two actions
    NEW new = Order {
        currency(new) <- currency(old); // a semicolon is put after each statement
        customer(new) <- customer(old);
    } // there is no semicolon in this line, because the operator ends in }
}

loadDefaultCurrency(ISTRING[30] name, INTEGER code) {
    NEW c = Currency {
        name(c) <- name;
        code(c) <- code;
    }
}
run () {
    loadDefaultCurrency('USD', 866);
    loadDefaultCurrency('EUR', 1251);
}


```

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

### Non-Materializable Property Example

Source: https://docs.lsfusion.org/Materializations

This example demonstrates a property that cannot be materialized because it is not NULL for an infinite number of dates. Such properties require re-calculation on each read.

```lsfusion
// such a property cannot be materialized, since it is not NULL for an infinite number of dates
lastDate(Customer customer, DATE date) = GROUP LAST date(Order order) IF customer(order) = customer AND date(order) < date ORDER order;
```

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

### HTTP GET Request with File Export

Source: https://docs.lsfusion.org/EXTERNAL_operator

Performs an HTTP GET request and saves the response to a file. Useful for downloading resources.

```lsfusion
EXTERNAL HTTP GET 'https://www.cs.cmu.edu/~chuck/lennapg/len_std.jpg' TO exportFile;
```

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

### HTTP GET Request with File Result

Source: https://docs.lsfusion.org/Access_to_an_external_system_EXTERNAL

Performs an HTTP GET request to fetch a file. The result is stored in exportFile and then opened.

```lsFusion
EXTERNAL HTTP GET 'https://www.cs.cmu.edu/~chuck/lennapg/len_std.jpg' TO exportFile;
open(exportFile());
```

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

### Start/Stop Application Server (systemctl)

Source: https://docs.lsfusion.org/Execution_auto

Manage the LSFusion application server service using systemctl commands on Linux.

```bash
systemctl stop lsfusion6-server
```

```bash
systemctl start lsfusion6-server
```

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

### Form Initialization and Scheduling Event Handlers

Source: https://docs.lsfusion.org/Event_block

Demonstrates setting up event handlers for form initialization (INIT) and scheduled periodic actions. The INIT handler runs when the form opens, and the SCHEDULE handler executes at a defined interval.

```lsfusion
EXTEND FORM POS 
    EVENTS 
        // when opening the form, executing the action to create a new receipt, 
        // which fills in the shift, cashier and other information 
        ON INIT createReceipt() 
        //apply every 60 seconds 
        ON SCHEDULE PERIOD 60 FIXED apply();
```

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

### OVERRIDE Operator Examples

Source: https://docs.lsfusion.org/OVERRIDE_operator

Demonstrates using the OVERRIDE operator to select values from different properties. The first example defines `overMarkup` which selects between a book's markup and its group's markup. The second example, `notNullDate`, provides a default date if the input date is NULL.

```lsfusion
CLASS Group;
markup = DATA NUMERIC[8,2] (Group);

markup = DATA NUMERIC[8,2] (Book);
group = DATA Group (Book);
overMarkup (Book b) = OVERRIDE markup(b), markup(group(b));

notNullDate (INTEGER i) = OVERRIDE date(i), 2010_01_01;
```

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

### Create System Windows

Source: https://docs.lsfusion.org/WINDOW_statement

Example of creating system windows with specific orientations, positions, alignments, and hidden titles/scrollbars.

```javascript
WINDOW logo HORIZONTAL POSITION(0, 0, 10, 6) VALIGN(CENTER) HALIGN(START) HIDETITLE HIDESCROLLBARS CLASS logoWindowClass();  
WINDOW root HORIZONTAL POSITION(10, 0, 70, 6) VALIGN(CENTER) HALIGN(CENTER) HIDETITLE HIDESCROLLBARS CLASS rootWindowClass();  
WINDOW system HORIZONTAL POSITION(80, 0, 20, 6) VALIGN(CENTER) HALIGN(END) HIDETITLE HIDESCROLLBARS CLASS systemWindowClass();  
  
WINDOW toolbar VERTICAL POSITION(0, 6, 20, 94) HIDETITLE CLASS toolbarWindowClass();  
  
```

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

### Example JSON Response for City Creation

Source: https://docs.lsfusion.org/v6/How-to_Interaction_via_HTTP_protocol

These are example JSON responses that can be received from the server after attempting to create a city, indicating success or failure.

```json
{"code":"0","message":"OK"}

```

```json
{"code":"1","message":"Invalid country code"}

```

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

### Launch lsFusion Platform with Docker Compose

Source: https://docs.lsfusion.org/Docker

Start the lsFusion platform containers (PostgreSQL, Application Server, Web client) by running this command in the directory containing your compose.yaml file.

```bash
docker-compose up -d
```

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

### Example JSON message data

Source: https://docs.lsfusion.org/v6/How-to_Custom_components_properties

An example of a JSON object representing a single chat message, conforming to the structure defined by the JSON operator.

```json
{
    "author":"John Doe",
    "time":"2021-10-05T15:28:05",
    "text":"Hello, Jack!",
    "own":1,
    "replyAuthor":"Jack Smith",
    "replyText":"Hello, John",
    "replyMessage":31302
}

```

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

### Get Order Attachment Content

Source: https://docs.lsfusion.org/v6/How-to_Interaction_via_HTTP_protocol

Retrieves the content of a specific file attachment using its internal identifier via an HTTP GET request.

```APIDOC
## getOrderAttachment (LONG id)

### Description
Retrieves the content of a specific file attachment.

### Method
GET

### Endpoint
http://localhost:7651/exec?action=getOrderAttachment

### Parameters
#### Query Parameters
- **p** (LONG) - Required - The internal identifier of the file.

### Response
#### Success Response (200)
- The content of the file. The `Content-Type` header will correspond to the file's extension.
```

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

### Start/Stop Web Server (Client) (systemctl)

Source: https://docs.lsfusion.org/Execution_auto

Control the LSFusion web server (client) service with systemctl commands on Linux.

```bash
systemctl stop lsfusion6-client
```

```bash
systemctl start lsfusion6-client
```

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

### Expand All Top Example

Source: https://docs.lsfusion.org/v6/EXPAND_operator

This example demonstrates recursively expanding all top-level elements within a specified object group. The OBJECTS block is ignored in this case.

```javascript
FORM expandCollapseTest  
    TREE elements e = NavigatorElement PARENT parent(e)  
    PROPERTIES(e) READONLY BACKGROUND NOT e IS NavigatorFolder VALUE, canonicalName, caption  
;

expandAllTop {
    EXPAND ALL TOP expandCollapseTest.e;
}

EXTEND FORM expandCollapseTest
    PROPERTIES() expandAllTop
;
```