File resource status shall be managed only for File mode answers

[dsauvage]

Description

As we can see in src/core/aws-server-http_utils.adb:1587

         File_Mode : constant Boolean :=
                       Response.Mode (Answer) in
                         Response.File .. Response.Stream;
         With_Body : constant Boolean := Messages.With_Body (Status_Code);
         File_Time : Ada.Calendar.Time;
         F_Status  : constant Resource_Status :=
                       Get_Resource_Status (C_Stat, Filename, File_Time);
         File      : Resources.File_Type;
      begin
         if F_Status in Up_To_Date .. Not_Found then
            if F_Status = Up_To_Date then
               --  [RFC 2616 - 10.3.5]
               Status_Code := Messages.S304;
            else
               --  File is not found on disk, returns now with 404
               Status_Code := Messages.S404;
            end if;

            Set_General_Header (Status_Code);

            Headers.Send_Header
              (Socket => Sock, Headers => H_List, End_Block => True);

            return;

File resource status is managed in all cases, even when Response.Mode (Answer) = Response.Message. This can happen in the following context;
Server A web service creates an answer using AWS.Response.File
Server B web service calls server A web service above using AWS.Client.Get and send back the response to the client

The patch below fix this issue by managing the file resource status only when the answer File_Mode is True, that is when Response.Mode (Answer) in Response.File .. Response.Stream. However shall we instead manage the file resource status for the File and File_Once modes only, keeping Stream mode out of it ?

         File_Mode : constant Boolean :=
                       Response.Mode (Answer) in
                         Response.File .. Response.Stream;
         With_Body : constant Boolean := Messages.With_Body (Status_Code);
         File_Time : Ada.Calendar.Time;
         F_Status  : constant Resource_Status :=
           (case File_Mode is
               when False => Changed,
               when True  => Get_Resource_Status (C_Stat, Filename, File_Time)
           );
         File      : Resources.File_Type;
begin
         if File_Mode and then F_Status in Up_To_Date .. Not_Found then
            if F_Status = Up_To_Date then

Patch
aws-server-http_utils.adb.patch.txt

[TurboGit]

Thanks, this makes sense indeed.

[TurboGit]

@dsauvage : It seems that this is already the case. If Filename = "" then Get_Resource_Status returns Changed, so I'm not sure this adds something. Right?

[dsauvage]

No, it is not already the case. If on server A, AWS.Response.File is called with Disposition => AWS.Response.Attachment, then when server B will send the data, it will have File_Mode set to Message, and Filename set to non empty, thus leading to an HTTP 404 error status, as the Mode is Message and server B is erroneously checking for the existence of a file that does not exist on server B.
The proposed patch solve this bug.

[TurboGit]

@dsauvage : After a second analysis I agree with you. I have missed the case of attachments and so your patch is correct. Thanks.