Compress Middleware and Tstream

BIZ TMS XData
1

Hi, In Xdata I send response in Tstream format from my services, for preserve entire content (Json already formatted). But Compress MIddleware don't compress response content.
Is this "by design"? I have to compress Tstream from myself?
Thanks

2

Compress middleware will only compress the response if some conditions are met:

  1. Client sends an accept-encoding header with value gzip or deflate
  2. Response size is bigger than the threshold specified in the middleware (1024 bytes by default)
  3. Response content-type is "compressible" (most text types, like text/html, text/plain, application/json, etc.
3

My test example (with Compress MIddleware in XdataServer middleware list):

function TGenService.JSONRPC(JsonRPC:string; method:string; params:TJsonObject; id:string): Tstream;
var
User: IUserIdentity;
begin
User:=Authorization('','10');
if (JsonRPC <> '2.0') or (trim(method) = '') then //or (id <= 0)
raise EXDataHttpForbidden.Create('JsonRPC non conforme');
TXDataOperationContext.Current.Response.Headers.setValue('content-type', 'application/json');
result:=JSONRPCMethods(method,params,User);
end;

But the stream is not compressed in Postman (size is always the same). Any hint on this?

Thanks

4

Are all conditions met?

5

Yes, I think. In the body result there is a Json.
I thought the only reason could be the Tstream type result...

6

Do you have a screenshot of the Postman request headers?
Do you have a screenshot showing the size of the response?
Are you sure Postman is not automatically decompressing the response?

7

Hi Wagner,
after some time,
yes, the Tstream in response isn't automatically compress in service.
I have 'Accept-Encoding = gzip, deflate' automatically in request headers.
(If I use an entity rest request have 'Accept-Encoding = gzip' without deflate).
Also in the browser the size received is the same, not compressed

8

I'm afraid I need a project and/or steps to reproduce the issue. Can you please send it?

9

Hi,
It's too complicated to extract the demo from my project, connected to the database.
But I can confidently say that if the service returns a Tstream, the response is NOT compressed.
I made 2 identical services, one that returns a Tstream and the other that returns a String.
The first does not return the compressed response, while the second respects gzip compression perfectly.
So it is certain that a response with Tstream is not compressed.
Should I consider this as a bug to be fixed?
Otherwise, can you tell me what I can use, components/functions already present in Xdata/Sparkle to compress the streams?
(which are actually ready-made json).
Thanks and good work!

10

If you're interested, part of a blog post I wrote a while ago covered how to add Brotli compression. I was after this particularly for the better compression rate when compressing JSON. The Actorious website has a lot of JSON, and this reduced the size of the transfers considerably, even compared to gzip.

1 Like
11

Have you paid attention the three points I made in my very first answer to this topic, especially item 3?

  1. Response content-type is "compressible" (most text types, like text/html, text/plain, application/json, etc.

When XData returns a TStream, you must set the content-type yourself: Service Operations | TMS XData documentation.

12

Uhm...
Ok, I will try setting content-type to 'Application/json'.
Thanks

13

Ok, it work.
The TXDataOperationContext.Current.Response.ContentType:= 'application/json' compression assignment was successful.
I instead focused on Accept-encoding and ContentEncoding :-)
Ok, thanks

I take this opportunity to make 2 requests:

  1. The ability to add control over the maximum length of strings in entity generation (as an option in Aurelius, in IDE). Currently I can only do this with the script in Data Modeler.
  2. The possibility of intercepting the SQL code generated by the Aurelius Linq in "simulation", time after time. For example, I need the select SQL code to make calls to the database and convert the result directly into json, without going through the entities, when I need a large amount of data and very quickly (in this case the orm is rather slow).
    But I have to say that I'm starting to like Xdata :-)
14

I will close this topic with the correct solution, then could you please open separate topics for the respective discussions?

15

ok, thanks

16

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