Calling a procedure(requiring multiple query parameters via OData/RestEasy) performing another REST call to a remote system

[fabiowebby]

Hi guys,

I hope you can help me with this as I do not seem to find any clear solution to this problem anywhere in the Internet and so it would be great if anyone could share some knowledge or experience on how to integrate Jboss DV with rest web services. A little background to start with, I have a Spring application on a remote server which exposes some REST endpoints performing CRUD operations on a Postgresql database hosted on the same machine and I have another Java application on another remote system which  captures some user input via HTML form and sends it to an underlining Java application via a Rest POST with JSON, this input should be passed to a procedure on the Teiid layer(via OData or Rest) which then performs a Rest call to the remote Spring application causing that input to be inserted in the Postgresql. In Teiid Designer I created a new REST Web Service source using the wizard available from the import menu which created a new source and view model containing a procedure to perform the Rest call to the remote Spring app with parameters passed to the procedure. If I preview the data within Teiid Designer passing parameters to the procedure everything works fine and it returns the three values in the Json response correctly but the problem is I don't know how to expose the procedure outside so that the Java layer can pass input parameters to the procedure on the Teiid layer. I followed these resources:

How to Consume a JSON REST Web Service in Teiid Designer

https://access.redhat.com/documentation/en-US/Red_Hat_JBoss_Data_Virtualization/6.1/html/User_Guide/chap-Metadata-specific_Modeling.html#sect-Web_Services_War_Generation

https://access.redhat.com/sites/default/files/attachments/consumerest-ws-datasource_version2.pdf

But I do not seem to figure how to pass multiple query parameters to this procedure via a Rest call to the Teiid layer out, all the examples I found all mention one parameter, I need to pass 6 of them, and even if I pass one it still does not work. I am definitely missing something but I don't know what as the official documentation is not helping at all. Therefore I would be extremely grateful if anyone could help with this or could point to some helpful resource for me to read further.

Thanks very much in advance.

Best Regards

Fabio

[tejones]

Hi Fabio,

For a DV REST service, define the REST:URI as myUri/{param1}/{param2}/{param3}/{param4} in the procedure REST properties with whatever import parameters you need. The REST procedure would just need the same input parameters defined.

Thanks,

Ted

[rareddy]

Fabio,

The rest service over the Postgres, is that one you developed or somebody else wrote? You can simplify the architecture by using Teiid using the Postgres as source and sending JDBC calls for CRUD, then on top of Teiid you can use OData or REST to issue calls from your application. I would prefer OData as it gives you good way to do querying as well as CRUD operations.

If you can not change REST service, then follow what Ted says above.

Also, in the generated web service [1], you can submit them using form parameters not as path parameters. Note that you can create this VDB in Designer, when you deploy it to the server the web service is automatically created if the metadata on the procedure is correctly defined, along with with "auto-generate" property.

[1] REST Service Through VDB - Teiid 8.11 (draft) - Project Documentation Editor

Ramesh..

[rareddy]

BTW if you go OData route, see this basic examples here Basic Tutorial | OData - The Protocol for REST APIs

[fabiowebby]

First of all, thank you very much Ramesh and Ted for your prompt reply and help, appreciated. I managed to make it work with the method Ted suggested earlier. I added charset, method(GET) and Rest endpoint name in the form: <URI_Name>/{param1}/{param2} to the procedure rest options. Then I created Vdb and Generated REST war file so I can call the procedure by :

http:/<host>/<VDB_name>/<My_View_Model>/<procedure_name>/<params>, it works but it returns an XML parsing error and only  the first string of the response is returned, the others are missing. Is it because I return strings as result of the procedure instead of XML? How do you query for the same procedure with params in OData style URL? I tried different options suggested in docs and forums but I seem to get a resteasy exceptions. Even though passing params like this works fine at the moment, it is not very scalable if parameters increase, how could I pass params in JSON via a POST call to the procedure? I think it is better if I manage to achieve this with POST and JSON because I have to pass more params to different Rest endpoints.

Thanks very much in advance for your help

Best Regards

Fabio

P.S

Ramesh to answer you question from earlier post. I have no control over REST application on the other side so I cannot connect to Postgresql via JDBC, I can only interact viat REST.

[rareddy]

For odata based procedure call see "Functions & Actions" at http://www.odata.org/getting-started/basic-tutorial

Yes, the inbuilt procedures must return XML or JSON. The "REST:PRODUCES" defines it is XML or JSON. If you want to return a scalar value or resultset, then the only option to access it readily with REST style is OData. Otherwise, you need to wrap it with another procedure that returns XML or JSON.

In 8.10 there are many improvements for POST. As I said earlier, in the POST, one can use FORM parameters not just PATH parameters. That way you have you can send any number of parameters. If not send a SQLXML or CLOB as input parameter to procedure and send body payload. See link I provided above.

Ramesh..