Thank you @ajgarlag
I've added your commit to #59648 which is patching a very related issue.

@nicolas-grekas Thanks. I have a related issue: We have a proxy implementation that forwards the received requests to an upstream server using PSR-7.

The upstream server was responding with a 5xx status code response because we were sending a Content-Type: application/x-www-form-urlencoded in GET requests.

When the ServerRequest object is created in PsrHttpFactory, the body stream wraps the fopen('php://input', 'r') resource which size is unknown ($psr7Request->getBody()->getSize() === null) but I think that when the method is not PATCH, PUT or POST, is safe to convert the body to string instead of streaming it because it will be usually an empty body.

This will prevent sending body content related headers in this case.

WDYT?

@@ -104,7 +104,7 @@ final class Psr18Client implements ClientInterface, RequestFactoryInterface, Str
 
             $options = [
                 'headers' => $headers,
-                'body' => 0 === $size ? '' : static fn (int $size) => $body->read($size),
+                'body' => 0 >= $size && false === array_search($request->getMethod(), ['PATCH', 'POST', 'PUT'], true) ? $body->getContents() : static fn (int $size) => $body->read($size),
             ];
 
             if ('1.0' === $request->getProtocolVersion()) {

I'd say this is on you when you create the request object...

I don't control how the request is created. The PSR7 request object is created using the Symfony\Bridge\PsrHttpMessage\Factory\PsrHttpFactory which calls Symfony\Component\HttpFoundation\Request::getContent.

I have a middleware to convert the body to string when the method is not expected to have a body, but I think this could be fixed in Symfony side.

I don't see how Symfony can do anything about it. GET requests can have a body so that the logic you suggest based on methods might work for you, but it won't for everybody. You're still in control of creating the HttpFoundation's Request object so you can do something about this.

I'll try to move my logic to the HttpFoundation request creation.

Thanks for the conversation.