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Introduction

 

In this blog I would like to show the basics of OData service development with SAP Gateway when using code based service implementation as it is shown in the upcoming SAP CodeJam events about OData service development with SAP Gateway.
Though the recommended approach for OData service development in the most recent SAP NetWeaver releases is to use CDS views there are still a number of use cases where code based service implementation is a valid option.

  1. Your SAP backend system is based on a SAP NetWeaver release 7.31 or earlier
  2. Your system is based on SAP NetWeaver 7.40 or later but the business logic you want to re-use has been implemented in ABAP code
  3. It is not possible to implement your business logic in CDS views

 

As an example we will use a simple OData model based that consist out of SalesOrders and SalesOrderItems with the option to navigate from a SalesOrder to the correponding line items.

 

If you are more interested in using CDS views please have a look at my following post: OData service development with SAP Gateway using CDS via Referenced Data Sources

If you want to know how to annotate services using code based implemenation you can have a look at my following post:

https://blogs.sap.com/2017/04/21/how-to-add-annotations-to-an-odata-service-using-code-based-implementation/

Changes

  • 28.06.2016  Fix for ABAP code: Replaced
    lv_osql_where_clause = io_tech_request_context->get_osql_where_clause( ).
                     through
    lv_osql_where_clause = io_tech_request_context->get_osql_where_clause_convert().
    because otherwise the statement GET SalesOrderSet?$filter=(Customer eq ‘100000000’) would not work because alpha conversion to ‘0100000000’ would not take place.
  • 24.11.2016 Moved ABAP source code into source code controls
  • 21.04.2017 Added a link that explains how to add annotations to the service.

 

Prequisites

 

The examples shown in this blog are based on the latest SAP NetWeaver release 750so that we can compare the different implementation approaches

 

 

Creating a basic OData service

 

We will perform the following steps:

 

  • Use the SAP Gateway Service Builder to create a new project
  • Import a DDIC structures for SalesOrder to create the data model
  • Generate, register and test the OData service using the Gateway Client
  • Perform a first implementation of the GET_ENTITYSET method

 

Create a new Service Builder project

 

  • Start the Gateway Service Builder by running transaction SEGW./wp-content/uploads/2016/05/image010_964920.png
  • Click on the Create Project button
    /wp-content/uploads/2016/05/image011_964921.png
  • Provide the following information:

Project: ZE2E100_XX

Description: ZE2E100_XX

Service Package: $TMP

Note: Replace XX with your session-id / group number.

 

/wp-content/uploads/2016/05/image012_964931.png

 

 

 

  • Press Continue
  • Press Save

Import a DDIC structures for SalesOrder

 

  • Right-click on Data Model and select Import –> DDIC Structure.

 

/wp-content/uploads/2016/05/image013_964932.png

  • In the first step of the wizard provide:In the field Name, enter SalesOrder
    In the field ABAP Structure, enter SEPM_ISOE.
    Click
    Next./wp-content/uploads/2016/05/image014_964940.png
  • In the second step of the wizard provide:Select the checkbox for SEPM_ISOE.
    Deselect the checkbox for MANDT,
    Click Next./wp-content/uploads/2016/05/image015_964941.png
  • In the third screen of the wizardSelect the checkbox Is Key for the field SALESORDER.
    Click Finish.
    /wp-content/uploads/2016/05/image016_964942.png
  • Expand Folder Properties and examine the entity SalesOrder and the entity set SalesOrderSet.(For example the property names, the Edm Core Type values and the ABAP field names)
    /wp-content/uploads/2016/05/image017_964943.png
  • Press Save
  • Press the Check Project Consistency button.
  • Verify that no errors were found.
  • Press the Generate Runtime Objects /wp-content/uploads/2016/05/image018_964944.pngbutton.Note: Using the Generate Runtime Objects button automatically saves the project.
  • Leave all values as defaulted and press Enter.

/wp-content/uploads/2016/05/image019_964946.png

  • Choose Local Object in the Create Object Directory Entry popup.
  • Verify that the generation was successful.

/wp-content/uploads/2016/05/image021_964945.png

 

Now you have created an (empty) service implementation in the SAP backend.

 

 

Register and Test the OData service using the Gateway client

 

  • Expand the node Service Maintenance and right-click on GW_HUB and select Register.

/wp-content/uploads/2016/05/image022_964947.png

  • In the Add Service popup leave all values as defaulted and press the Local Object button to assign the artifacts to the $tmp package. Then press Enter to continue

/wp-content/uploads/2016/05/image023_964948.png

  • Double-click on the GW_HUB entry under Service Maintenance. Verify that the registration status on the right-hand side is showing a green traffic light.

/wp-content/uploads/2016/05/image024_964949.png

  • In the navigation tree right-click on GW_HUB and select SAP Gateway Client.Alternatively click on the SAP Gateway Client button in the detail section.
    /wp-content/uploads/2016/05/image025_964951.png
  • Confirm the warning popup that warns you that you will be redirected to the selected system. Select Yes.
  • This opens up the SAP Gateway Client in a new screen. The URI of the service document is already defaulted.
    Press the Execute button.

/wp-content/uploads/2016/05/image027_964955.png

  • As a result you get the service document of your OData service in the HTTP response window

/wp-content/uploads/2016/05/image028_964956.png

  • Press the Button “Entity Sets” and select SalesOrderSet.

/wp-content/uploads/2016/05/image029_964958.png

  • After pressing Execute button which executes the following URI
    /sap/opu/odata/SAP/ZE2E100_<XX>_SRV/SalesOrderSet
    you see an error message that indicates that the method SALESORDERSET_GET_ENTITYSET has not yet been implemented.

/wp-content/uploads/2016/05/image030_964959.png

 

 

Provision the GET_ENTITYSET method of the service using ABAP code

 

  • Open the Service Builder Project again (if you have closed it)
  • Expand the node Service Implementation and expand SalesOrderSet.
    Now right-click on GetEntitySet(Query) and choose
    Go to ABAP Workbench.

/wp-content/uploads/2016/05/image031_964960.png

  • Confirm the warning“Operation SALESORDERSET_GET_ENTITYSET has not yet been implemented”
  • Switch to edit mode, scroll down to the method SALESORDERSET_GET_ENTITYSET and make sure to select it.Click on the Redefine Method button.

     

  • Use Copy&Paste to copy the entire coding shown below into the salesorderset_get_entityset method. Please note: This is a new syntax for ABAP SQL.
    method SALESORDERSET_GET_ENTITYSET.
    
      select * from sepm_i_salesorder_e
          into corresponding fields of table @et_entityset.
    
    endmethod.    
    

/wp-content/uploads/2016/05/image034_964962.png

    • Info: The replaced coding selects data from the CDS view sepm_i_salesorder_e.The results are filled into the corresponding fields of the return structure et_entityset of the get-entityset method.
      This works out of the box since the structure SEPM_ISOE was used to create the entity type using DDIC import. This structure is the so called sqlViewName of the CDS view sepm_i_salesorder_e. The source code of the DDL source can be viewed using the report RUTDDLSSHOW.
  • Click on Activate.
  • Confirm the activation popup.
  • Navigate back to the Service Builder main screen using the green back /wp-content/uploads/2016/05/image035_964963.pngbutton multiple times.
  • In the navigation tree right-click on GW_HUB and select SAP Gateway Client.Alternatively click on the SAP Gateway Client button in the detail section.

/wp-content/uploads/2016/05/image036_964964.png

  • This opens up the SAP Gateway Client in a new screen. The URI of the service document is already defaulted.
    Press the Button “Entity Sets” and select SalesOrderSet
    The request URI field will contain the following value:

/sap/opu/odata/SAP/ZE2E100_<XX>_SRV/SalesOrderSet

        (Replace <XX> by your group number.)

 

After pressing Execute button you see a list of sales orders.

 

/wp-content/uploads/2016/05/image037_964965.png

 

  • You can retrieve the number of sales orders by adding “/$count” to the request URI/sap/opu/odata/SAP/ZE2E100_<XX>_SRV/SalesOrderSet/$countReplace <XX> by your group number and press Execute

 

/wp-content/uploads/2016/05/image038_964966.png


Add support for $filter to your code

 

  • Open the Service Builder Project again
  • Expand the node Service Implementation and SalesOrderSet and choose the entry GetEntitySet (Query).
    Now right-click on GetEntitySet (Query) and choose
    Go to ABAP Workbench.

/wp-content/uploads/2016/05/image039_964970.png

  • This time the ABAP editor will open the method salesorderset_get_entityset  immediately.
    Switch to the change mode and replace the code with the code shown below.
    The code retrieves the $filter statement as an osql statement for the where clause.
    The data is retrieved and inserted into the return table et_entityset.

 

 

  method SALESORDERSET_GET_ENTITYSET.

data: lv_osql_where_clause type string.
lv_osql_where_clause = io_tech_request_context->get_osql_where_clause( ).
select * from sepm_i_salesorder_e
      into corresponding fields of table @et_entityset
      where (lv_osql_where_clause).

  endmethod.

/wp-content/uploads/2016/05/image040_964971.png

  • Click on Activate.
  • Navigate back to the Service Builder main screen using the back button
  • In the navigation tree right-click on GW_HUB and select SAP Gateway Client.Alternatively click on the SAP Gateway Client button in the detail section.
  • This opens up the SAP Gateway Client in a new screen. The URI of the service document is already defaulted.
  • Replace the URI with the following:

    /sap/opu/odata/SAP/ZE2E100_<XX>_SRV/SalesOrderSet?$filter=Grossamountintransaccurrency ge 100000&$select=Salesorder,Grossamountintransaccurrency,Transactioncurrency&$format=json

    Replace <XX> by your group number and press Execute

    This will deliver a list of four sales orders whose gross amount exceeds 100.000 Euro and will only show the sales order number and the gross amount.

    
    
    
     500000005
     500000030
     500000034
     500000045
    
     

/wp-content/uploads/2016/05/image041_964973.png

 

Add support for additional query options to your code

 

 

  • Open the Service Builder Project again
  • Expand the node Service Implementation and right-click on SalesOrderSet and choose the entry GetEntitySet (Query).
    Now right-click on GetEntitySet (Query) and choose
    Go to ABAP Workbench.

 

  • This time the ABAP editor will open the method salesorderset_get_entityset immediately.
  • Switch to the edit mode.
    Replace the code with the code shown below.
    The code retrieves the values for $top and $skip and the $filter statement as an osql statement for the where clause.The data is retrieved and in the end it is checked whether $inlinecount is used (which is a default for SAPUI5)

 

  method SALESORDERSET_GET_ENTITYSET.

    data: lv_osql_where_clause type string,
          lv_top               type i,
          lv_skip              type i,
          lv_max_index         type i,
          n                    type i.
*- get number of records requested
    lv_top = io_tech_request_context->get_top( ).
*- get number of lines that should be skipped
    lv_skip = io_tech_request_context->get_skip( ).
*- value for maxrows must only be calculated if the request also contains a $top
    if lv_top is not initial.
      lv_max_index = lv_top + lv_skip.
    endif.
    lv_osql_where_clause = io_tech_request_context->get_osql_where_clause( ).

    select * from sepm_i_salesorder_e
      into corresponding fields of table @et_entityset
      up to @lv_max_index rows
      where (lv_osql_where_clause).
*- skipping entries specified by $skip
    if lv_skip is not initial.
      delete et_entityset to lv_skip.
    endif.
*-  Inlinecount - get the total numbers of entries that fit to the where clause
    if io_tech_request_context->has_inlinecount( ) = abap_true.
      select count(*)  from   sepm_i_salesorder_e where (lv_osql_where_clause) .
      es_response_context-inlinecount = sy-dbcnt.
    else.
      clear es_response_context-inlinecount.
    endif.


  endmethod.
  • Click on Activate.
  • Navigate back to the Service Builder main screen using the back button  multiple times.
  • In the navigation tree right-click on GW_HUB and select SAP Gateway Client.Alternatively click on the SAP Gateway Client button in the detail section.
  • This opens up the SAP Gateway Client in a new screen. The URI of the service document is already defaulted.
  • Replace the URI with the following:/sap/opu/odata/SAP/ZE2E100_<XX>_SRV/SalesOrderSet?$filter=Grossamountintransaccurrency ge 100000&$select=Salesorder,Grossamountintransaccurrency,Transactioncurrency&$top=2&$skip=1&$inlinecount=allpages&$format=jsonReplace <XX> by your group number and press Execute
    This will deliver a list of only 2 sales orders whose gross amount exceeds 100.000 EUR. The first sales order 500000005 is skipped and only the first 2 of the rest of the list (highlighted in bold) are shown.
    The inlinecount however shows that in total 40 sales orders would fit to the filter criteria.

    500000005
    500000030 <–
    500000034 <–
    500000045
    Please note: $skip, $top and $inlinecount are used for client side paging. SAPUI5 uses this to calculate how many pages one has to navigate through.

 

/wp-content/uploads/2016/05/image043_964974.png

 

 

What is now left is the implementation of the GET_ENTITY method of the entity set SalesOrderSet and the modelling and implementation of the navigation between sales order header and the line items.

 

This will be described in the second part of this blog post OData service development with SAP Gateway – code-based service development – Part II because the editor refused to let me add any additional screen shots at this point 😉 .

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16 Comments

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  1. Chris Whealy

    If like me, you find that when testing your service in the Gateway Client txn, you get a German error message popping up “HTTPIO_ERROR_CUSTOM_MYSAPSSO-Fehlermeldung beim Senden der Daten”, then (as the message so clearly indicates?), this means the profile parameter for your ABAP system to control the creation and use of SSO2 logon tickets has not been configured correctly.

    See André’s other blog for details of how to fix this: http://scn.sap.com/community/gateway/blog/2015/11/26/sso-problem-with-the-sap-gateway-client-iwfndgwclient


    Chris W

    (0) 
  2. Samuli Kaski

    It is probably worth mentioning that Gateway doesn’t support all the where clauses OSQL supports, e.g. I had to code support for Contains Pattern (CP).

    (1) 
    1. Mike Reader

      Samuli,

      I was trying to use the OData canonical function ‘contains’ – which I assume would map to the CP you are referring to (in the ideal world) … but as you say it is not supported.

      I was thinking about combining startswith and endswith to achieve a similar result.

      Thoughts?

      Thanks, Mike

      (0) 
      1. Samuli Kaski

        It might work depending on your use case. In my case, I detect in the DPC_EXT class if SELOPT-SIGN = ‘I’, SELOPT-OPTION = ‘EQ’ and SELOPT-LOW contains ‘*’ and if it does, I simply change SELOPT-OPTION to ‘CP’ before handing over for processing.

        (0) 
  3. Joachim Rees

    Thanks for sharing, André!

    Do you actually recommend using SE24 to get the ABAP-Code in the generated classes?

    Shouldn’t we use eclipse for that?

    (I’m currently trying to get to love eclipse, overcoming the “it’s easier the old way (as I have been doing that for a long time -> Eclipse is something new)”-feeling.

    That’s why I always get a little insecure when seeing the traditional ABAP Workbench used in modern examples like yours.

    best

    Joachim

    (0) 
  4. Daniel Su

    Hi Andre,

    Thank for sharing, I am a beginner in fiori. I am learning how to develop fiori app.

    I refer to your infomation, follow by implementation,

    in step “Expand the node Service Maintenance and right-click on GW_HUB and select Register”

    I can’t see the GW_HUB, what is the reason?

    Best regards,

    Daniel

    (0) 
      1. Daniel Su

        Hi Andre,

        Thanks for your reply.

        I will go to implement refer document.

        So,  after my configuration is complete, and then re-created the object, it will appear.

        In addition, prior to implementation of the part, I still need to configure other settings?

        Thanks for your guidance.

        Best Regards,

        Daniel

        (0) 
  5. Joachim Rees

    André, as we just discussed:

    select * from sepm_i_salesorder_e
    into corresponding fields of table @et_entityset
    up to @lv_max_index rows
    where (lv_osql_where_clause).

    “add ORDER BY here!!
    *- skipping entries specified by $skip
    if lv_skip is not initial.
    delete et_entityset to lv_skip.
    endif.


    I think you have to add an “ODER BY” clause here (e.g. order by PRIMARY KEY) , in order to ensure that the results comming back from the select are sorted in the same way with every execution of the select statement!


    best

    Joachim


    Edit: also see current discussion here: Re: ORDER BY in Custom-Code for HANA

    (0) 
  6. Meenakshi Raina

    Hi Andre,

    Very nice blog.

    I have followed your steps, and achieved the result. Just one doubt, here we are importing a DDIC structure , say , VBAK table. Then we did some in the class in se24 and moved the contents to et_entityset table. Hence in such cases, our et_entityset is of the type of VBAK table.

    What if I don’t want to import a DDIC structure ?

    I have done some code in my SE24 class, but i dont understand what should be the type of my et_entityset table ?

    Thanks and Regards

    Meenakshi

    (0) 
    1. Andre Fischer Post author

      The type of et_entityset is based on the type defined in the MPC class.

      ls_headerdata type zcl_ze2e100_xx_mpc=>ts_salesorder.

      I would always recommend to use DDIC structures but you can also create entity types manually usign SEGW.

      Best Regards,

      Andre

       

      (0) 

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