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The RESTful Web Service plugin allows exposing business logic as a RESTful Web Service.
About RESTful Web ServicesRESTful Web Services utilize the features of the HTTP Protocol to provide the API of the Web Service. For example, it uses the HTTP Request Types to indicate the type of operation:
Using these 4 HTTP Request Types a RESTful API mimics the CRUD operations (Create, Read, Update & Delete) common in transactional systems. A defining feature of REST is that it is stateless: each call the to a RESTful Web Service is completely stand-alone: it has no knowledge of previous requests. Implementing a RESTful Web Service in ServoyA RESTful Web Service endpoint is created by defining a Form in a Solution and implementing one or more of the following methods to the Form:
The RESTful Web Service endpoint is then available through the URL With 2019.09 the {formName} can also be a scope so you don't need to create a form (thats more a ui element) If the method for one of the HTTP Request Types is not implemented, that operation is not available on the endpoint and when attempted to be called a METHOD_NOT_ALLOWED (HTTP 405) error will be thrown. The RESTful Web Service plugin does not have any client side functions or properties: all its magic happens by implementing the methods with the predefined
Keeping It StatelessRESTful Web Services are to be stateless. The RESTful Web Service plugin internally uses a pool of Headless Clients to handle multiple concurrent requests to the REStful Web Service API. As subsequent requests to the RESTful Web Service API might be handled by different headless clients in the pool of clients configured for the plugin, no state should be preserved in the headless client at the end of the call to the API. Therefore, make sure any state is cleared at the end of logic. This means at least the following:
Supporting GET RequestsGET Requests are supported on the endpoint if the If the return value is a JavaScript object, it will be serialized and then placed in the body of the HTTP Response. See Returning Binary Data for more info on returning binary content. If the return value of the method is null, a NOT_FOUND response (HTTP 404) will be generated. See what arguments you can receive in this method call. Supporting POST RequestsPOST Requests are supported on the endpoint if the The body content of the HTTP Request is passed into the If the body content cannot be converted to a JavaScript object / string based on the Content-Type, an INTERNAL_SERVER_ERROR response (HTTP 500) will be generated. If the content in the body of the HTTP Request is missing, a NO_CONTENT response will be generated (HTTP 204). The
The method can optionally return a JavaScript primitive/array/object or a byte array, from 2020.12 on you can return a JSFile object so you can stream large files to the client. If the return value is a JavaScript object, it will be serialized and then placed in the body of the HTTP Response. See Returning Binary Data for more info on returning binary content. See what other arguments you can receive in this method call. Supporting DELETE RequestsDELETE Requests are supported on the endpoint if the
See what arguments you can receive in this method call. Supporting PUT RequestsPUT Requests are supported on the endpoint if the
The body content of the HTTP Request is passed into the If the body content cannot be converted to a JavaScript object / string based on the Content-Type an INTERNAL_SERVER_ERROR response (HTTP 500) will be generated. If the content in the body of the HTTP Request is missing, a NO_CONTENT response will be generated (HTTP 204). See what other arguments you can receive in this method call. Adding
Additional arguments - when adding Extra Data to the Request URL or return values in ws_authenticateAdditional data can be added in the URL of the HTTP Requests. There are two variations and how they are made available in the Additional URL Fragments Additional URL fragments can be added to the URL like:
The additional URL fragments Query Parameters If the URL contains Query parameters, these will be passed into the Note that if custom endpoint restrictions are implemented and the Combining Additional URL Fragments and Query Parameters
Example A HTTP Get Request on URL The
Supported Content Types & EncodingThe plugin supports the following Content Types:
Request Content-Type and Encoding The Content-Type of the HTTP Request can be explicitly set by the caller using the
For requests that specify body content (POST and PUT Requests (resp.
When the Content-Type cannot be determined, an UNSUPPORTED_MEDIA_TYPE response will be generated (HTTP 415). Response Content-Type and Encoding By default, the plugin will respond with the same content type as used in the HTTP Request. The client calling the RESTful Web Service can request a different response content type by specifying the desired content type for the Response by setting the The response will be encoded with the If the encoding of the response needs to be different than the request encoding, this can be specified in the HTTP Request by setting the charset value in the Accept header:
Returning Binary DataThe RESTful Web Services plugin supports returning binary data in GET operations. Binary data could for example be the content of a dataprovider of type MEDIA or the contents of a file read from disk. In this case, the body of the response will contain the actual stream of bytes. Clients consuming the web service must be able to handle the binary response. When the consuming client specifies the From 2020.12 on if you return large binary data, please use a JSFile wrapper around an actual file on disk, then the bytes are just streamed directly from disk to the client over the http request without the need to read the bytes fully in memory. Setting Custom HeadersCustom headers can be set in the response by implementing the
Each key/value pair will be added as Header to the HTTP Response. Returning Custom Status CodesWhile some of the HTTP Response status codes are hardcoded in the RESTful Webservices plugin, it is possible to control the HTTP Status codes from within the For example, when a
It is also possible to set the body content of the HTTP Response with a more elaborate message to give more context to the returned status code:
For convenience purposes, all available HTTP Status Codes are also listed under the HTTP Plugin, so instead of throwing the number 404 in the first example, a more readable way would be to throw plugins.http.HTTP_STATUS.SC_NOT_FOUND For additional explanation of all the status codes, see List_of_HTTP_status_codes on Wikipedia. Authentication/AuthorizationBy default access to any endpoint in unrestricted. The plugin supports 2 modes of implementing Authentication and authorization.
Global Restrictions Based on Servoy SecurityBy setting the plugins server property The endpoints must be called with HTTP Basic authentication to provide a username and password. The username/password supplied in the HTTP Request is validated against the users registered in Servoy's built-in security system and additionally against group membership. Access is denied if the user does not exist or the supplied password is incorrect, or the user doesn't belong to one of the specified groups. When access is denied, an UNAUTHORIZED response is generated (HTTP 401). Custom Endpoint RestrictionsFor each endpoint custom authentication and authorization can be added by implementing the If the method returns false or null an UNAUTHORIZED response is generated (HTTP 401). Any other return value will be added as an extra query parameter with the key JSONP supportThe plugin supports so-called JSONP: a variation of JSON that allows cross domain data retrieval. The JSONP variation can be invoked by added a 'callback' parameter to the HTTP Request URL:
When invoked with the value "myCallback" for the 'callback' parameter, the returned JSON value will be wrapped in a function call to the
Versioning support{serverUrl}/servoy-service/rest_ws/v2/mysolution/myform_or_scope/ or {serverUrl}/servoy-service/rest_ws/mysolution/v2/myform_or_scope/Is This is supported (the 'v ' has to be there and the '2 ' must be a number). Then whatWhat is looked up is in the 'myform_v2' form or the 'scope_v2' scope (for theversion 2 of the api). (supported since 2019.09) Nested call support{serverUrl}/servoy-service/rest_ws/mysolution/myscope/mymethod/mymethod2/arg1 The plugin will now lookup in 'mysolution ' on the 'myscope ' scope a method likenamed 'ws_read_mymethod_mymethod2 and'; if that one is found it will call it with the'arg1 ' as an argument. If the'ws_read_mymethod_mymethod2' method is not found it will try: 'ws_read_mymethod' (that will then willget 2 arguments : 'mymethod2' and 'arg1') and if that one is not found either it will fallback tito 'ws_read' (with 3 arguments). Read more about method arguments. Pool of ClientsTo service the requests to the RESTful Web service API, the plugin creates a pool of (headless) clients. The maximum number of clients allowed can be set using the When there are more concurrent requests than the number of clients in the pool, by default the requests will wait until a client becomes available in the pool. This behavior can be altered by setting the
Client pluginCode running inside a rest-ws request can access the request and the response using the rest_ws client plugin. For example, retrieve a custom header sent by the client:
Note that the client-plugin can only be used within a request handler, the function See API documentation for the plugin. Sample SolutionA sample solution is included in the Servoy distribution (servoy_sample_rest_ws.servoy), detailing how to retrieve data from the HTTP Request and to return a response. More information on RESTful Web ServicesSee the following links for more information on RESTful Web Services:
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