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- Overview
- Importing a Webservice into a project
- Import
- "Project explorer" pane: viewing a webservice
- Description and properties of a Webservice
- Updating the description of a Webservice
- Properties of a Webservice modifiable in the editor
- Using a Webservice
- Principle
- How to set values in the HTTP header of a SOAP webservice call?
- Asynchronous Webservice call
- Properties associated with the web service
- Properties available on the types of variables
- Advanced operations of the XML stream of the Webservice
- Special case: the Webservice returns a result whose type is not recognized by WINDEV, WEBDEV and WINDEV Mobile
- Distributing a WINDEV application that uses a Webservice
Importing/Consuming Webservices
WINDEV, WEBDEV and WINDEV Mobile allow you to directly import Webservices into your applications. A Webservice is a set of entry points made available to the users in order to perform different processes. For example, a service for remote access provides the processes used to access the data. The exchanges of information with a Webservice are performed in XML format and they use the SOAP (Simple Object Access Protocol) and HTTP protocols. From the description in WSDL format (Web Services Description Language) of this service, WINDEV, WEBDEV or WINDEV Mobile will automatically generate the WLanguage types and functions corresponding to the programming interface of Webservice. To use the Webservice, all you have to do is use the functions generated during the import. This help page presents: Importing a Webservice into a project Import To import a Webservice: - On the "Project" tab, in the "Project" group, expand "Import" and select "A Webservice".
The Webservice import wizard starts.
- In the wizard, the presentation screen is displayed. Go to the next step.
- Specify the location of the WSDL. This file corresponds to the webservice description. It contains the description of each function found in the Webservice as well as their parameters. Two methods can be used to locate the WSDL:
- from a URL, HTTP address where the WSDL is found.
Remarks: - You have the ability to specify the username and the password if an authentication is required.
- The "Proxy" button is used to configure the proxy options if necessary.
- from an XML file found on the current computer.
- Validate the wizard. A message is displayed, indicating that the import is ended.
- The Webservice is automatically added into the "Project explorer" pane (in the "Webservices" branch). It is ready to use.
"Project explorer" pane: viewing a webservice The imported Webservice is in the "Webservices" folder of the "Project explorer" pane: The structure includes: - the name of the Webservice.
- the name of each function.
- the name of a structure containing either the call parameters, or the return values.
- the name of each variable in the structure.
Description and properties of a Webservice Updating the description of a Webservice When a Webservice evolves (corrections, new versions, etc.), its description may also evolve. To update the description of a Webservice in your project: - Select the Webservice in the "Project explorer" pane.
- Select "Update" from the popup menu.
Remark: The Webservices imported by using the compatibility mechanism with the earlier versions cannot be updated. Properties of a Webservice modifiable in the editor To modify the properties of a Webservice in the editor: - Select the Webservice in the "Project explorer" pane.
- Select "Description" in the context menu.
- The window of properties is displayed. The following properties can be modified in this window:
- The import address of Webservice: it is the URL used to reach the WSDL describing the Webservice.
- The username and the password used to import the WSDL.
Principle To use a Webservice, you must: - Declare 2 variables: a variable used to specify the call parameters and a variable used to retrieve the response.
- Initialize each variable of the call structure.
Important: the order of assignment of variables is used in the XML generated in the SOAP request. It is therefore necessary to assign the variables in the order specified in the documentation of the webservice function. - Call the Webservice function by passing the call variable as parameter and retrieve the response variable in return.
Example: trackingSearch is trackSearch
trackingSearchRes is resultTrackSearch
trackingSearch.accountNumber = 99999999
trackingSearch.consigneesCountry = "FR"
trackingSearch.consigneesZipCode = "37100"
trackingSearch.sendersRef = "111111"
trackingSearchRes = TrackingServiceWSService.trackSearch(trackingSearch)
IF ErrorOccurred() THEN
Trace("Failed to call the Webservice: " + ErrorInfo(errFullDetails))
ELSE
Trace("Webservice successfully run")
END In most cases, the result returned by the Webservice is in XML format. Therefore, the XML functions must be used to decode the response. How to set values in the HTTP header of a SOAP webservice call? To set values in the HTTP header of a SOAP webservice call: - Declare a wsRequest variable.
- Use the HTTPHeader property to set the header values.
- Call the webservice procedure by specifying the name of the wsRequest variable as the first parameter.
Example:
C is wsRequest
C.HTTPHeader["key"] = "Value"
// Call the Webservice procedure
// while passing the header and the expected parameters
WebServiceProc(C, param1_WS, param2_WS)
// Displays the request sent
Trace(C.XMLSource) Remark: On the server side, it is possible to retrieve the header using the WebserviceReadHTTPHeader function. Asynchronous Webservice call In some cases, the call to a Webservice may take too long. It may be necessary to make an asynchronous call to the Webservice, using the following syntax: AFTER <Result> = <Webservice call procedure> DO
<Code executed only if the Webservice has been executed and has sent the response>
END
<Code executed directly after the call to the Webservice> Using this syntax, you can prevent the call to the Webservice from blocking the application. The program continues to run even if the Webservice has not yet responded. The previous example becomes:
trackingSearch is trackSearch
trackingSearchRes is resultTrackSearch
trackingSearch.accountNumber = 99999999
trackingSearch.consigneesCountry = "FR"
trackingSearch.consigneesZipCode = "37100"
trackingSearch.sendersRef = "111111"
AFTER trackingSearchRes = TrackingServiceWSService.trackSearch(trackingSearch) DO
IF ErrorOccurred() THEN
Trace("Failed to call the Webservice: " + ErrorInfo(errFullDetails))
ELSE
Trace("Webservice successfully run")
END
END For more details, see AFTER statement. Properties associated with the web service To handle a Webservice through programming, simply use the name of the Webservice (found in the "Project explorer" pane). Remark: You can drag and drop directly from the "Project explorer" pane to the code editor to insert the name of the Webservice. The following properties can be modified through programming: | | | | Name | Type used | Effect |
|---|
| Address | Character string | Used to replace the call address of Webservice described in the WSDL by another URL. This property is useful if the web service is hosted on different servers. This property has the following format: "http://server:port/webservice_path". For a web service generated with WINDEV and deployed on a WEBDEV Application Server, it is the URL of the "awws" file. Remarks: - The modification of this property replaces all the URLs described in the WSDL.
- If this property corresponds to an empty string (""), the URLs described in the WSDL will be re-used.
| | Integer constant | Used to force the HTTP authentication method: - auAutomatic (default value): automatic authentication method.
- auBasic: Basic authentication method.
- auNegotiate: Negotiate authentication method.
 Caution: This authentication method is not supported by Linux executables.
| | IgnoreError | Combination of constants | Used to ignore the certificate errors. the following constants can be used:- httpIgnoreInvalidCertificate: Used to ignore an invalid certificate or a certificate coming from an unknown company.
- httpIgnoreInvalidCertificateName: Used to ignore the name of the site found in the certificate.
- httpIgnoreExpiredCertificate: Used to ignore the date of the certificate.
- httpIgnoreRedirectToHTTP: Used to redirect to a non-secure server.
- httpIgnoreRedirectToHTTPS: Used to redirect to a secure server.
- httpIgnoreRevocation: Used to ignore the check in the list of revoked certificates.
Remarks:  The errors regarding the security of transactions are ignored. The IgnoreError property is not available.   Only the following errors are supported: httpIgnoreExpiredCertificate, httpIgnoreInvalidCertificate, httpIgnoreInvalidCertificateName, httpIgnoreRevocation. The other errors are ignored. For backward compatibility, all the errors are ignored by default.
| | MethodHTTP | Integer constant | HTTP method used to call the Webservice:- httpPost (default value): POST method
- httpPut: PUT method
Not available.
| | Password | Character string | Password used for authentication in the HTTP requests sent to the web service. This name is used only if authentication is required to access the server where the web service is hosted. | | Port | Character string | Name of the port defined in the WSDL. It is the port used to communicate with the server that hosts the web service. Contact your network manager or the owner of the web service. | | User | Character string | Username used for authentication in the HTTP requests sent to the web service. This name is used only if authentication is required to access the server where the web service is hosted.
With the Negotiate authentication method, the domain must be added to the user depending on the configuration: myWebservice..User = "DOMAIN\User" myWebservice..User = "User@DOMAIN" | | VersionHTTP | Integer constant | HTTP version used by the server: - httpVersion2: HTTP version 2.0. If the server does not support this version, an older version is used.
- httpVersion2Only: Forces HTTP version 2.0: if the server does not support this version, a fatal error is displayed.
- httpVersion1_1: HTTP version 1.1.
- httpVersion1_0: HTTP version 1.0.
- httpVersionDefault: HTTP version 1.0.
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Remark: - If a username and a password are specified, the authentication of the HTTP requests will be done by using the "Basic" authentication schema, in which the parameters are in readable format in the HTTP request. We recommend that you use HTTPS requests if the authentication is required.
- If the server that hosts the Webservice requires a Windows authentication in HTTP, HTTPConfigure must be called before consuming the Webservice (in order to use Internet Explorer for the HTTP requests).
- The maximum timeout can be specified with HTTPTimeOut.
Caution: The properties modifiable in the editor and the properties modifiable through programming have no link. Properties available on the types of variables The types of variables automatically declared when importing the WSDL propose several properties: | | | | Name | Type used | Effect |
|---|
| Count | Integer | Number of elements of this type in the response of the Webservice. A Webservice can return arrays of variables. The Count property allows you to get the size of the returned array and the [ ] operator allows you to access the elements of the array. | | Exist | Boolean | - True if the type of variable exists in the Webservice response,
- False otherwise.
| | Type | Character string | Name of the variable type. This property is used when a Webservice is likely to return responses of different types. | | Value | Variant | Value of the variable. Remark: This property is accessed by default when only the variable name is used. For example: myWebservice.RequestVariable = EDT_Value is equivalent to: myWebservice.RequestVariable..Value = EDT_Value |
Advanced operations of the XML stream of the Webservice In some cases, you may have to handle the XML data stream exchanged with the Webservice. Some Webservices ask for example to add headers into their XML stream to allow the authentication or return meta information in the response headers. The following functions can be used to respond to these particular requests: | | | SOAPAddAttribute | Declares the additional attributes (not found in the WSDL) on a Webservice variable automatically generated. It is used in advanced programming when the WSDL returned by the Webservice does not exactly correspond to the expected type. | | SOAPAddHeader | Adds custom headers into a call to a Webservice. | | SOAPGetHeader | Re-reads the information found in the header of the Webservice response. | | SOAPPrepare | Builds the request to the Webservice for a given function and parameters but it does not send it. |
Special case: the Webservice returns a result whose type is not recognized by WINDEV, WEBDEV and WINDEV Mobile The types of variables available in WINDEV and the ones available in a SOAP Webservice can differ. The simple types (boolean, integer, etc.) and the complex types (datetime, duration, structures, arrays of simple types and array of structures, nested structures, etc.) used in the Webservice are automatically converted into the WLanguage format (and conversely) when the service is imported into a project. The Array types are also supported. The most evolved types (classes, advanced types of WLanguage, etc.) are processed as character strings in the WLanguage code. These character strings contain the XML code corresponding to the type of variable returned by the Webservice and to its content. Therefore, if a Webservice returns a result as a class instance, this result will be processed in the procedure as a character string in XML format. Then, you will have to process this character string (in WLanguage) in order to extract the desired information. For more details, see the XML functions. Remarks: - If the Webservice returns a structure, the name of the members found in the return structure is case sensitive.
- If you are using a structure as parameter of a Webservice function and if a DATE member is not assigned, the following error will be displayed: "The 0000-00-00 value does not respect the XSD schema".
Distributing a WINDEV application that uses a Webservice To distribute an application that uses a Webservice, simply include the file that describes the Webservice (.wsdl file) in the library of the application. In order for the application to be able to run the Webservice, the end-user computers must have an access to Internet. Remark: Before distributing an application that uses a Webservice, it is recommended to check the license and the distribution rights of this service (in case there is a free for the service).
Related Examples:
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Training (WINDEV): WD Webservice Client
[ + ] This example illustrates the use of WebServices. It explains how to retrieve, from a WebService, images according to keywords. This project is the client that connects to the "WD Webservice Server" WebService.
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Training (WINDEV): WD Webservice Server
[ + ] This example illustrates the use of the WebServices. It explains how to create a WebService by providing some images according to keywords. This project is the WebService that is used th the WD Webservice Client project.
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