add smart response checks for ref discovery (#1942)

* add smart response checks for ref discovery

Added content-type check and content regex check for reference discovery
see https://github.com/schacon/igithub/blob/master/http-protocol.txt

* move ref check constants to TRANSPORT class

the check constants - content regex and responce Content-Type - don't have to be global right now so moved from zif_abapgit_definitionsto zcl_abapgit_git_transport

* PP and activate

src/git/zcl_abapgit_git_transport.clas.abap

@@ -33,6 +33,12 @@ CLASS zcl_abapgit_git_transport DEFINITION
                  receive TYPE string VALUE 'receive',       "#EC NOTEXT
                  upload  TYPE string VALUE 'upload',        "#EC NOTEXT
                END OF c_service.
+    CONSTANTS: BEGIN OF c_smart_response_check,
+                 BEGIN OF get_refs,
+                   content_regex TYPE string VALUE '^[0-9a-f]{4}#',
+                   content_type  TYPE string VALUE 'application/x-git-<service>-pack-advertisement',
+                 END OF get_refs,
+               END OF c_smart_response_check.
 
     CLASS-METHODS branch_list
       IMPORTING iv_url         TYPE string
@@ -83,12 +89,19 @@ CLASS zcl_abapgit_git_transport IMPLEMENTATION.
   METHOD branch_list.
 
     DATA: lv_data TYPE string.
-
+    DATA: lv_expected_content_type TYPE string.
 
     eo_client = zcl_abapgit_http=>create_by_url(
       iv_url     = iv_url
       iv_service = iv_service ).
 
+    lv_expected_content_type = c_smart_response_check-get_refs-content_type.
+    REPLACE '<service>' IN lv_expected_content_type WITH iv_service.
+
+    eo_client->check_smart_response(
+        iv_expected_content_type = lv_expected_content_type
+        iv_content_regex         = c_smart_response_check-get_refs-content_regex ).
+
     lv_data = eo_client->get_cdata( ).
 
     CREATE OBJECT eo_branch_list
@@ -186,7 +199,7 @@ CLASS zcl_abapgit_git_transport IMPLEMENTATION.
               zcl_abapgit_git_utils=>get_null( ) &&
               ` ` &&
               lv_cap_list &&
-              zif_abapgit_definitions=>c_newline.          "#EC NOTEXT
+              zif_abapgit_definitions=>c_newline.           "#EC NOTEXT
     lv_cmd_pkt = zcl_abapgit_git_utils=>pkt_string( lv_line ).
 
     lv_buffer = lv_cmd_pkt && '0000'.
@@ -260,14 +273,14 @@ CLASS zcl_abapgit_git_transport IMPLEMENTATION.
           && ` ` && lv_capa && zif_abapgit_definitions=>c_newline. "#EC NOTEXT
       ELSE.
         lv_line = 'want' && ` ` && <ls_branch>-sha1
-          && zif_abapgit_definitions=>c_newline.           "#EC NOTEXT
+          && zif_abapgit_definitions=>c_newline.            "#EC NOTEXT
       ENDIF.
       lv_buffer = lv_buffer && zcl_abapgit_git_utils=>pkt_string( lv_line ).
     ENDLOOP.
 
     IF iv_deepen = abap_true.
       lv_buffer = lv_buffer && zcl_abapgit_git_utils=>pkt_string( 'deepen 1'
-        && zif_abapgit_definitions=>c_newline ).           "#EC NOTEXT
+        && zif_abapgit_definitions=>c_newline ).            "#EC NOTEXT
     ENDIF.
 
     lv_buffer = lv_buffer

src/zcl_abapgit_http_client.clas.abap

@@ -9,15 +9,17 @@ CLASS zcl_abapgit_http_client DEFINITION PUBLIC CREATE PUBLIC.
       set_digest
         IMPORTING io_digest TYPE REF TO zcl_abapgit_http_digest,
       send_receive_close
-        IMPORTING
+        IMPORTING iv_data        TYPE xstring
-                  iv_data        TYPE xstring
+        RETURNING VALUE(rv_data) TYPE xstring
-        RETURNING
-                  VALUE(rv_data) TYPE xstring
         RAISING   zcx_abapgit_exception,
       get_cdata
         RETURNING VALUE(rv_value) TYPE string,
       check_http_200
         RAISING zcx_abapgit_exception,
+      check_smart_response
+        IMPORTING iv_expected_content_type TYPE string
+                  iv_content_regex         TYPE string
+        RAISING   zcx_abapgit_exception,
       send_receive
         RAISING zcx_abapgit_exception,
       set_headers
@@ -33,7 +35,7 @@ ENDCLASS.
 
 
 
-CLASS ZCL_ABAPGIT_HTTP_CLIENT IMPLEMENTATION.
+CLASS zcl_abapgit_http_client IMPLEMENTATION.
 
 
   METHOD check_http_200.
@@ -41,7 +43,6 @@ CLASS ZCL_ABAPGIT_HTTP_CLIENT IMPLEMENTATION.
     DATA: lv_code TYPE i,
           lv_text TYPE string.
 
-
     mi_client->response->get_status(
       IMPORTING
         code   = lv_code ).
@@ -66,6 +67,29 @@ CLASS ZCL_ABAPGIT_HTTP_CLIENT IMPLEMENTATION.
   ENDMETHOD.                                                "http_200
 
 
+  METHOD check_smart_response.
+
+    DATA: lv_content_type TYPE string.
+    DATA: lv_data         TYPE string.
+
+    IF iv_expected_content_type IS NOT INITIAL.
+      lv_content_type = mi_client->response->get_content_type( ).
+      IF lv_content_type <> iv_expected_content_type.
+        zcx_abapgit_exception=>raise( 'Wrong Content-Type sent by server - no fallback to the dumb protocol!' ).
+      ENDIF.
+    ENDIF.
+
+    IF iv_content_regex IS NOT INITIAL.
+      lv_data = mi_client->response->get_cdata( ).
+      FIND REGEX iv_content_regex IN lv_data.
+      IF sy-subrc <> 0.
+        zcx_abapgit_exception=>raise( 'Wrong Content sent by server' ).
+      ENDIF.
+    ENDIF.
+
+  ENDMETHOD.
+
+
   METHOD close.
     mi_client->close( ).
   ENDMETHOD.

src/zif_abapgit_definitions.intf.abap

@@ -21,7 +21,7 @@ INTERFACE zif_abapgit_definitions PUBLIC.
            ty_file_signature WITH UNIQUE KEY path filename .
   TYPES:
     BEGIN OF ty_file.
-      INCLUDE TYPE ty_file_signature.
+          INCLUDE TYPE ty_file_signature.
   TYPES: data TYPE xstring,
          END OF ty_file .
   TYPES:
@@ -107,7 +107,7 @@ INTERFACE zif_abapgit_definitions PUBLIC.
   TYPES: ty_yes_no TYPE c LENGTH 1.
 
   TYPES: BEGIN OF ty_overwrite.
-      INCLUDE TYPE ty_item.
+          INCLUDE TYPE ty_item.
   TYPES: decision TYPE ty_yes_no,
          END OF ty_overwrite.
 
@@ -216,7 +216,7 @@ INTERFACE zif_abapgit_definitions PUBLIC.
     ty_seocompotx_tt TYPE STANDARD TABLE OF seocompotx WITH DEFAULT KEY .
   TYPES:
     BEGIN OF ty_tpool.
-      INCLUDE TYPE textpool.
+          INCLUDE TYPE textpool.
   TYPES:   split TYPE c LENGTH 8.
   TYPES: END OF ty_tpool .
   TYPES: