fglrestful

The fglrestful tool produces REST web services stub files for client programs using an OpenAPI specification.

Syntax

fglrestful [ options ] service

options are described in fglrestful options and in fglrestful network options.
service is the OpenAPI service definition file or URL.

Options

Table 1. fglrestful Options
Options	Description
`-V` or `--version`	Displays version information.
`-h` or `--help`	Displays options for the tool.
`-l` or `--list` `{` `path \| resource` `}`	List all the paths or resources of a service. For an example, go to List path or resource (--list).
`-o` or `--output filename`	Specify a name for the output stub file. For an example, go to Generate the stub file.
`-n` or `--name resource`	In a service providing access to one or more resources, specify the creation of a stub file for a given resource. For an example, go to Generate stub file for resource.
`-p` or `--prefix prefix`	Set a prefix for constants and variables.
`--typePrefix prefix`	Set a prefix for types. Where `prefix` allows you to add a prefix in front of the name of types in a JSON schema. For an example, go to Set types with prefix value (--typePrefix).
`-b` or `--binary` `{` `byte \| file` `}`	Specify that binary types are generated as either `BYTE` or `FILE` types in the stub.
`-f` or `--format` `{` `xml \| json` `}`	Specify the preferred REST format (xml or json). You must use lowercase xml or json in the command.
`-a` or `--oauth` `{` `yes \| no` `}`	Specify if OAuth specification should be generated or not: With option "yes", OAuth support code is generated even if the OpenAPI documentation does not specify it. With option "no", OAuth support code is not generated even if the OpenAPI documentation requires it. If you do not use the `--oauth` argument, fglrestful generates the OAuth support code by default if it is specified in the OpenAPI documentation.
`--legacyJSONApi`	Generate stub file with legacy JSON API (`util.JSON`) when used with the --output option. For details, go to Usage.
`--ignore-restrictions`	Ignore OpenAPI format keywords (`maxLength`, `multipleOf`, `minimum`, `maximum`) when converting OpenAPI types to BDL types in the stub. Affected types: `CHAR(N)`, `VARCHAR(N)`, `DECIMAL(P,S)`, and `DATETIME`. For the conversion rules, go to Converting OpenAPI types to BDL in client stubs.
`--datetime-fraction { 1 \| 2 \| 3 \| 4 \|5 }`	Specify `DATETIME` fraction qualifier. The default is `NULL`, meaning `YEAR TO SECOND`. If value is between 1 and 5, fglrestful generates `YEAR TO FRACTION(N)` where `N` is the value provided. Important: The option applies only to properties with `format: date-time`, which a Genero REST service (GWS 6.00.03 and later) generates only when its datetimeSerializationMode option is `"RFC3339/UTC"` or `"RFC3339/TZO"`. In the default `"FGL"` mode, these properties have no `format`, so fglrestful generates `STRING` for them. Set the mode in the REST service before you fetch its OpenAPI document.
`--interval qualifier`	Specify the `INTERVAL` qualifier used for OpenAPI duration properties (`type: string`, `format: duration`). The default is `DAY(9) TO FRACTION(5)`. Use `STRING` instead of an `INTERVAL` qualifier to generate `STRING` variables for duration properties. For an example, go to Set the INTERVAL qualifier for durations (--interval). Important: The option applies only to properties with `format: duration`, which a Genero REST service (GWS 6.00.03 and later) generates only when its intervalSerializationMode option is `"ISO8601"`. In the default `"FGL"` mode, these properties have no `format`, so fglrestful generates `STRING` for them. Set the mode in the REST service before you fetch its OpenAPI document.
`--datetime-interval-format format`	Specify the JSON serialization format for `DATETIME` and `INTERVAL` values in generated stubs: `native` (default): the generated stub does not call `json.Serializer.setOption()`. If your application does not change the serializer options, `DATETIME` and `INTERVAL` values use the native BDL string format (for example, `2024-11-05 09:15:58`). If your application changes the serializer options, the stub uses those settings. A stub generated with `iso8601` or `iso8601-local` does not restore the previous options, so a `native` stub called after it uses the ISO 8601 settings. `iso8601` (UTC): the stub sets `datetimeSerializationMode` to `"RFC3339/UTC"` and `intervalSerializationMode` to `"ISO8601"`. `iso8601-local` (local timezone offset): the stub sets `datetimeSerializationMode` to `"RFC3339/TZO"` and `intervalSerializationMode` to `"ISO8601"`. This option affects only values sent in requests. Received `DATETIME` and `INTERVAL` values in responses are auto-detected; both native and ISO 8601 formats are accepted. The option has no effect on properties that the stub declares as `STRING`, because the stub sends a `STRING` value as is. Against a REST service in the default `"FGL"` mode, set the serialization mode in the service before you generate the stub. An invalid `format` value stops fglrestful with `Error: invalid DATETIME/INTERVAL format` and a non-zero exit status. For an example, go to Serialize DATETIME and INTERVAL in ISO 8601 (--datetime-interval-format).
`-t` or `--token token`	Specify the access token value if the service is protected by an access token.
`-k` or `--tokenfile filename`	Specify the access token file if the service is protected by an access token.
`--comment`	Add comments to the generated stub file. For an example, go to Output comments (--comment).
`-W` or `--Warnings` `{` `yes \| no` `}`	Specify if warnings should be output or not. By default the option value is `yes`, meaning the warnings are reported. For an example, go to Output warnings (-W).
`--no-merge-allof`	Disable merging of properties in `allOf` schemas. For the types the tool generates from a composition, go to allOf schema composition.

Table 2. Network options (when specifying a URL)
Options	Description
`--proxy location`	Connect via proxy where `location` is `host[:port]` or `ip[:port]`.
`--pLogin login`	Proxy authentication login.
`--pPass pass`	Proxy authentication password.
`--hLogin login`	HTTP authentication login.
`--hPass pass`	HTTP authentication password.

Usage

Use fglrestful to generate GWS client stub files from an OpenAPI version 3 specification. The typical command form is:

fglrestful -o stubname spec

where spec is either an OpenAPI file or a service URL. Run fglrestful -h to list all available options.

If the service uses the Genero REST high-level API, the specification is available by default at the ?openapi.json query string. For example, to generate a stub from a service running locally:

fglrestful -o myStub http://localhost:8090/MyService?openapi.json

If your service uses versioning, request a specific version by appending &version=version-name to the query string. For examples, go to Generate stub file for a version.

fglrestful returns a non-zero exit code on error, making it suitable for use in scripts and makefiles.

The fglrestful tool recognizes all media types derived from JSON via the +json structured syntax suffix defined by RFC 6839 (external link). The subtype preceding +json must not be empty; the comparison is case-insensitive. All recognized types are handled like application/json: JSON serialization of the request body, JSON parsing of the response, and generation of content handling code from the associated OpenAPI schema.

Table 3. Supported media types in OpenAPI content sections
Media type	Description
`application/json`, `text/json`	Standard JSON types, supported in all versions.
`application/*+json`	Any application subtype with the `+json` suffix. Common examples: `application/ld+json`: JSON Linked Data; enriches JSON with metadata such as `@id` and `@context`. `application/problem+json`: RFC 7807 standard format for returning error details in JSON. `application/vnd.api+json`: JSON:API specification for building consistent REST APIs. `application/hal+json`: Hypertext Application Language (HAL); a JSON format for hypermedia APIs.
`text/*+json`	Any text subtype with the `+json` suffix.
`text/event-stream`	`text/event-stream` is the media type for Server-Sent Events (SSE), a web standard for streaming real-time updates from a server to a client. fglrestful does not generate response-handling code for this type. Behavior depends on the operation: If the operation also declares another response content type, the stub is generated against that type. If `text/event-stream` is the only declared response content type, the operation is skipped. The tool issues a warning naming the skipped operation and writes the operation as a comment in the generated .4gl file. You must implement SSE handling for this operation manually.

Date-time and duration options

Use --datetime-fraction and --interval to override the default BDL types that fglrestful generates for OpenAPI temporal properties. Use --datetime-interval-format to control how DATETIME and INTERVAL values serialize to JSON.

Table 4. Default BDL types for OpenAPI temporal properties
Option	OpenAPI property	Default BDL type	Override example
`--datetime-fraction`	`type: string`, `format: date-time`	`DATETIME YEAR TO SECOND`	`--datetime-fraction 3` generates `DATETIME YEAR TO FRACTION(3)`
`--interval`	`type: string`, `format: duration`	`INTERVAL DAY(9) TO FRACTION(5)`	`--interval "HOUR TO SECOND"` generates `INTERVAL HOUR TO SECOND`; `--interval STRING` generates `STRING`

For examples, go to Set the INTERVAL qualifier for durations (--interval) and Serialize DATETIME and INTERVAL in ISO 8601 (--datetime-interval-format).

Warning:

BDL INTERVAL qualifiers fall into one of two incompatible classes: year-month (YEAR to MONTH) or day-time (DAY to FRACTION). If the service returns a year-month duration (for example P2Y3M) and the stub uses a day-time qualifier (the default DAY(9) TO FRACTION(5)), the runtime raises error -15807. Use --interval "YEAR TO MONTH" when the service returns only year-month durations, or --interval STRING when the specification mixes both classes.

Note:

Only qualifiers that end in FRACTION preserve fractional seconds: DAY, HOUR, MINUTE, or SECOND TO FRACTION(n). If the qualifier you pass to --interval does not end in FRACTION — for example HOUR TO SECOND — the runtime silently drops any fractional seconds in a received duration value; PT1.5S becomes PT1S without error. The default qualifier DAY(9) TO FRACTION(5) preserves up to five fractional-second digits.

In the next sections there are examples of common commands used by REST web service developers.

Generate the stub file

Use the -o / --output option to name the output stub file:

Using the URL of the running service:

fglrestful -o myStub http://localhost:8090/MyService?openapi.json

Or using an OpenAPI documentation file. If you access the OpenAPI information on the browser, you can copy the description to a file and save the file with an openapi extension, for example, myservice.openapi. Then run the command to generate the stub file from this:
```
fglrestful -o myStub myservice.openapi
```
Tip:
In Genero Studio, you can place the openapi file in your project and the stub file is generated from it when you compile the file. For more information, refer to the Genero Studio User Guide.

The generated client stub file, myStub in the example, is a Genero BDL file (.4gl).

By default, fglrestful uses the JSON streaming API to generate the stub file code. It is possible to use the old JSON API (util.JSON) instead by specifying the --legacyJSONApi option:

fglrestful -o myStub --legacyJSONApi myservice.openapi

Generate stub code for a `+json` media type

If an OpenAPI specification declares a response using an application/problem+json content type, fglrestful recognizes it and generates the corresponding client stub code. For example, given this OpenAPI response declaration:

responses:
  '400':
    description: Bad request
    content:
      application/problem+json:
        schema:
          $ref: '#/components/schemas/Problem'

Running fglrestful generates a stub function containing a CASE block that tests the response Content-Type and retrieves the body:

WHEN retCode == 400 # Bad request
  IF contentType MATCHES "*application/problem+json*" THEN
    # Parse FILE response
    LET getproblemjson_400 = resp.getFileResponse()
    RETURN C_GETPROBLEMJSON_400, resp_body.*
  END IF
  LET wsError.code = retCode
  LET wsError.description = "Unexpected Content-Type"
  RETURN -1, resp_body.*

Set types with prefix value (`--typePrefix`)

Use --typePrefix to avoid naming conflicts with Genero reserved words or library names (such as "base" or "util"). In this example, the prefix "foo" is added to all named types:

fglrestful -o myStub --typePrefix foo http://localhost:8090/MyService?openapi.json

In the generated stub file, the "Base" type is renamed, and whereever it is referenced, to "foo_Base":

# components/schemas/foo_Base
PUBLIC TYPE foo_Base RECORD
    id INTEGER,
    path STRING
END RECORD
#...
PUBLIC TYPE useBase RECORD
  id INTEGER,
  country foo_Base,
  postal_code VARCHAR
END RECORD

List path or resource (`--list`)

Use --list to output all paths or resources of a service. These commands list the resources:

using the URL of the running service:

fglrestful -l resource http://localhost:8090/MyService?openapi.json

or using a specification file:

fglrestful -l resource myservice.openapi

Generate stub file for resource

Use -n to generate a stub file for a specific resource. These commands generate a stub for the "users" resource:

using the URL of the running service:

fglrestful -n users -o myUsersStub http://localhost:8090/MyService?openapi.json

or using a specification file:

fglrestful -n users -o myUsersStub myservice.openapi

Generate stub file for a version

Use the &version=version-name query string to generate a stub for a specific version. These commands generate a stub for "v2":

using the URL of the running service (the URL must be enclosed in quotes):

fglrestful -o myVersion2Stub "http://localhost:8090/MyService?openapi.json&version=v2"

or using an OpenAPI documentation file that contains the version 2 operations only:
```
fglrestful -o myV2Stub myserviceV2.openapi
```

If the requested version does not exist, the 404 error will be returned.

Output comments (`--comment`)

Use --comment to include WSDescription and WSTypeDescription text in the generated stub file. These commands generate a stub with comments:

using the URL of the running service:

fglrestful -o myStub --comment http://localhost:8090/MyService?openapi.json

or using a specification file:

fglrestful -o myStub --comment  myservice.openapi

The descriptive text appears in the generated stub file in curly braces, for example:

PUBLIC TYPE user RECORD {This is a user}

 p_resourceId INTEGER {this is the customer id}

The WSDescription set on the ATTRIBUTES() clause of the function is not affected. It is always generated; even if the --comment option is not specified.

Set the INTERVAL qualifier for durations (`--interval`)

Use --interval to override the default INTERVAL DAY(9) TO FRACTION(5) qualifier for duration properties. This command generates INTERVAL HOUR TO SECOND variables:

fglrestful --interval "HOUR TO SECOND" -o stub myapi.json

To generate STRING variables instead:

fglrestful --interval STRING -o stub myapi.json

Serialize DATETIME and INTERVAL in ISO 8601 (`--datetime-interval-format`)

This command generates a stub that sends DATETIME values in RFC 3339 UTC and INTERVAL values as ISO 8601 durations:

fglrestful --datetime-interval-format iso8601 -o stub myapi.json

In the generated stub, the option translates to json.Serializer.setOption() calls placed before each JSON request body is sent:

CALL req.setHeader("Content-Type", "application/json")
CALL json.Serializer.setOption("datetimeSerializationMode", "RFC3339/UTC")
CALL json.Serializer.setOption("intervalSerializationMode", "ISO8601")
VAR writer = req.beginJSONRequest()
CALL writer.startJSON()
CALL json.Serializer.variableToJSON(p_body, writer)
CALL writer.endJSON()
CALL req.endJSONRequest(writer)

For the values of these options, go to datetimeSerializationMode and intervalSerializationMode.

For the output formats, go to DATE, DATETIME, and INTERVAL conversions.

Note: This option has no effect when used with --legacyJSONApi. Free-form and multipart JSON bodies always use the native format. fglrestful outputs the warning: Option --datetime-interval-format has no effect with --legacyJSONApi.

Output warnings (`-W`)

The tool outputs warnings by default, and you run -W no to silence them. These commands write warnings to standard output:

using the URL of the running service:

fglrestful -W yes -o myStub http://localhost:8090/MyService?openapi.json

or using a specification file:

fglrestful -W yes -o myStub myservice.openapi

The warning message gives the path in the openapi.json file where you locate the issue, and gives the reason.

Warning in /paths/Property/GetAllProperties/{applicationID}/{includeWillBeSold}/{update}/get/responses
Reason : Unsupported media='text/plain' on type='WebAPI_CreditAnalysis_Models_PropertyContainer'

Errors are reported by default. The error message gives same kind of path, but with Error in instead of Warning in.

fglrestful

Syntax

Options

Usage

Date-time and duration options

Generate the stub file

Generate stub code for a +json media type

Set types with prefix value (--typePrefix)

List path or resource (--list)

Generate stub file for resource

Generate stub file for a version

Output comments (--comment)

Set the INTERVAL qualifier for durations (--interval)

Serialize DATETIME and INTERVAL in ISO 8601 (--datetime-interval-format)

Output warnings (-W)

Generate stub code for a `+json` media type

Set types with prefix value (`--typePrefix`)

List path or resource (`--list`)

Output comments (`--comment`)

Set the INTERVAL qualifier for durations (`--interval`)

Serialize DATETIME and INTERVAL in ISO 8601 (`--datetime-interval-format`)

Output warnings (`-W`)