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JerryWang
Advisor
Advisor
8,242

Recently I meet with this cookie issue so I document it as a blog in case any other guys might meet with the same problem.



I am trying to create some Opportunity transaction data by consuming OData service via CL_HTTP_CLIENT. Since this is a update operation which needs to be finished by HTTP POST, so a CSRF token is needed in this HTTP post. Let's first have a look what is a typical scenario running in Chrome extension postman:
1. Perform a HTTP get operation with header field x-csrf-token = fetch to get a valid CSRF token from http response header field.



2. launch a HTTP post request using the CSRF token got from previous step,



And a new opportunity could successfully be created in postman:



However, when I implement the above mentioned scenario in ABAP, I meet with trouble. Instead of the expected successful creation message, I always get the error message "CSRF token validation failed".



Issue trouble shooting


Let's go back to postman scenario. Although it seems only the header field x-csrf-token is specified in http request, however there is another field cookie which is added to http request under the hood.



We could get this cookie field from previous HTTP get request which is responsible for CSRF token retrieve:



It means in ABAP implementation, we need to first retrieve BOTH CSRF token and cookie field from the first HTTP GET request, and then added these two fields to the request of second HTTP POST request which actually performs the opportunity creation.



This solution is also explained in this thread


I just added the complete source code of my implementation here and feel free to reuse it.

The ABAP report to create Opportunity by consuming OData service:


zcl_odata_tool=>get_csrf_token_and_cookie( IMPORTING et_cookies = DATA(lt_cookie)
ev_token = DATA(lv_token) ).
zcl_odata_tool=>create_opp( iv_token = lv_token it_cookies = lt_cookie ).

Source code for ZCL_ODATA_TOOL:


CLASS zcl_odata_tool DEFINITION
PUBLIC
FINAL
CREATE PUBLIC .
PUBLIC SECTION.
CLASS-METHODS get_csrf_token_and_cookie
EXPORTING
!et_cookies TYPE tihttpcki
!ev_token TYPE string .
CLASS-METHODS create_opp
IMPORTING
!iv_token TYPE string
!it_cookies TYPE tihttpcki .
PROTECTED SECTION.
PRIVATE SECTION.
ENDCLASS.
CLASS ZCL_ODATA_TOOL IMPLEMENTATION.
METHOD create_opp.
DEFINE insert_line.
lv_body = lv_body && &1.
lv_body = lv_body && cl_abap_char_utilities=>newline.
END-OF-DEFINITION.

DATA:lo_http_client TYPE REF TO if_http_client,
lv_status TYPE i,
lt_fields TYPE tihttpnvp,
lv_sysubrc TYPE sysubrc.

CALL METHOD cl_http_client=>create_by_url
EXPORTING
url = 'https://<your C4C host>/sap/c4c/odata/v1/c4codata/$batch'
IMPORTING
client = lo_http_client
EXCEPTIONS
argument_not_found = 1
plugin_not_active = 2
internal_error = 3
OTHERS = 4.

ASSERT sy-subrc = 0.
lo_http_client->propertytype_accept_cookie = if_http_client=>co_enabled.

CALL METHOD lo_http_client->request->set_method( if_http_request=>co_request_method_post ).

lo_http_client->request->set_header_field( name = 'Content-Type' value = 'multipart/mixed; boundary=batch_1' ).
lo_http_client->request->set_header_field( name = 'x-csrf-token' value = iv_token ).
lo_http_client->request->set_header_field( name = 'Authorization' value = 'your basic authentication code' ).
LOOP AT it_cookies ASSIGNING FIELD-SYMBOL(<cookie>).
lo_http_client->request->set_cookie( name = <cookie>-name
value = <cookie>-value ).
ENDLOOP.
DATA: lv_body TYPE string.

insert_line '--batch_1'.
insert_line 'Content-Type: multipart/mixed; boundary=changeset_1'.
lv_body = lv_body && cl_abap_char_utilities=>cr_lf.
*
insert_line '--changeset_1'.
insert_line 'Content-Type: application/http'.
insert_line 'Content-Transfer-Encoding: binary'.
lv_body = lv_body && cl_abap_char_utilities=>cr_lf.

insert_line 'POST OpportunityCollection HTTP/1.1'.
insert_line 'Content-Length: 5000'.
insert_line 'Accept: application/json'.
insert_line 'Content-Type: application/json'.

lv_body = lv_body && cl_abap_char_utilities=>cr_lf.
insert_line '{'.
insert_line '"AccountID": "8000018122",'.
insert_line '"OwnerID": "8000018122",'.
insert_line `"Name": {"content": "Testing ticket creation via OData Jerry1"}`.
insert_line '}'.
insert_line '--changeset_1--'.
lv_body = lv_body && cl_abap_char_utilities=>cr_lf.
insert_line '--batch_1--'.

lo_http_client->request->set_cdata( data = lv_body ).
CALL METHOD lo_http_client->send
EXCEPTIONS
http_communication_failure = 1
http_invalid_state = 2
http_processing_failed = 3.

ASSERT sy-subrc = 0.

CALL METHOD lo_http_client->receive
EXCEPTIONS
http_communication_failure = 1
http_invalid_state = 2
http_processing_failed = 3.

IF sy-subrc <> 0.
CALL METHOD lo_http_client->get_last_error
IMPORTING
code = lv_sysubrc
message = DATA(ev_message).
WRITE: / 'error occurred during receive data' COLOR COL_NEGATIVE.
RETURN.
ENDIF.
DATA(lv_json) = lo_http_client->response->get_cdata( ).
WRITE:/ lv_json.
ENDMETHOD.

METHOD get_csrf_token_and_cookie.
DATA: lo_http_client TYPE REF TO if_http_client,
lv_status TYPE i,
lt_fields TYPE tihttpnvp,
lv_sysubrc TYPE sysubrc.

CALL METHOD cl_http_client=>create_by_url
EXPORTING
url = 'https://<your C4C host>/sap/c4c/odata/v1/c4codata/'
IMPORTING
client = lo_http_client
EXCEPTIONS
argument_not_found = 1
plugin_not_active = 2
internal_error = 3
OTHERS = 4.

ASSERT sy-subrc = 0.
lo_http_client->propertytype_accept_cookie = if_http_client=>co_enabled.

CALL METHOD lo_http_client->request->set_method( if_http_request=>co_request_method_get ).
lo_http_client->request->set_header_field( name = 'x-csrf-token' value = 'Fetch' ).
lo_http_client->request->set_header_field( name = 'Accept' value = 'application/json' ).
lo_http_client->request->set_header_field( name = 'Content-Type' value = 'application/json' ).
lo_http_client->request->set_header_field( name = 'Authorization' value = 'Your basic authentication' ).

CALL METHOD lo_http_client->send
EXCEPTIONS
http_communication_failure = 1
http_invalid_state = 2
http_processing_failed = 3.

ASSERT sy-subrc = 0.

CALL METHOD lo_http_client->receive
EXCEPTIONS
http_communication_failure = 1
http_invalid_state = 2
http_processing_failed = 3.

IF sy-subrc <> 0.
CALL METHOD lo_http_client->get_last_error
IMPORTING
code = lv_sysubrc
message = DATA(ev_message).
WRITE: / 'Error when getting token:', ev_message.
RETURN.
ENDIF.

lo_http_client->response->get_header_fields( CHANGING fields = lt_fields ).

READ TABLE lt_fields ASSIGNING FIELD-SYMBOL(<field>) WITH KEY name = 'x-csrf-token'.
ev_token = <field>-value.

lo_http_client->response->get_cookies( CHANGING cookies = et_cookies ).
lo_http_client->close( ).

ENDMETHOD.
ENDCLASS.

Further reading


You can find a list of all other blogs related to OData written by Jerry.











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