Is there a way to parse HTTP headers following a esp_http_client_fetch_headers() call (IDFGH-14204)

[Dazza0]

Is your feature request related to a problem?

Hi, I'm currently trying to do a native HTTP request using the esp_http_client.h API i.e., without calling the esp_http_perform() function (similar to the http_native_request() function in the esp_http_client example. The reason being that I want to manually fetch headers and parse them, before conditionally sending a GET request for the actual data payload.

However, after calling esp_http_client_fetch_headers() to fetch the headers, the esp_http_client.h API doesn't provide a way to access the buffer storing the headers.

Is there a recommended way to get access to those headers and parse them?

Describe the solution you'd like.

No response

Describe alternatives you've considered.

No response

Additional context.

No response

[nopnop2002]

Is this no good?
https://github.com/espressif/esp-idf/tree/master/examples/protocols/http_request

You can get HTTP headers.

HTTP/1.0 200 OK
Accept-Ranges: bytes
Age: 372137
Cache-Control: max-age=604800
Content-Type: text/html
Date: Tue, 10 Dec 2024 02:05:49 GMT
Etag: "3147526947"
Expires: Tue, 17 Dec 2024 02:05:49 GMT
Last-Modified: Thu, 17 Oct 2019 07:18:26 GMT
Server: ECAcc (lac/5598)
Vary: Accept-Encoding
X-Cache: HIT
Content-Length: 1256
Connection: close

You can still get the header with this.
https://github.com/espressif/esp-idf/tree/v5.3.2/examples/protocols/esp_http_client

I (9666) HTTP: HTTP_EVENT_ON_HEADER, key=Content-Type, value=application/rss+xml
I (9666) HTTP: HTTP_EVENT_ON_HEADER, key=Server, value=Apache/2.4.37 (Rocky Linux) OpenSSL/1.1.1k
I (9666) HTTP: HTTP_EVENT_ON_HEADER, key=ETag, value="b6752d053f69b6ed4c117feead10316d8937aad89bf27ee230b50b55a09f33a0"
I (9686) HTTP: HTTP_EVENT_ON_HEADER, key=Access-Control-Allow-Origin, value=*
I (9686) HTTP: HTTP_EVENT_ON_HEADER, key=expiry_extended_seconds, value=0
I (9696) HTTP: HTTP_EVENT_ON_HEADER, key=Cache-Control, value=no-transform, max-age=120
I (9706) HTTP: HTTP_EVENT_ON_HEADER, key=Date, value=Tue, 10 Dec 2024 02:34:07 GMT
I (9716) HTTP: HTTP_EVENT_ON_HEADER, key=Content-Length, value=3545
I (9716) HTTP: HTTP_EVENT_ON_HEADER, key=Connection, value=keep-alive

[Dazza0]

@nopnop2002

Is this no good?
https://github.com/espressif/esp-idf/tree/master/examples/protocols/http_request

That also works, but that would be operating at a lower level of abstraction. I was hoping to operate that the ESP HTTP Client layer where TLS is handled.

You can still get the header with this.
https://github.com/espressif/esp-idf/tree/v5.3.2/examples/protocols/esp_http_client

I (9666) HTTP: HTTP_EVENT_ON_HEADER, key=Content-Type, value=application/rss+xml
I (9666) HTTP: HTTP_EVENT_ON_HEADER, key=Server, value=Apache/2.4.37 (Rocky Linux) OpenSSL/1.1.1k
I (9666) HTTP: HTTP_EVENT_ON_HEADER, key=ETag, value="b6752d053f69b6ed4c117feead10316d8937aad89bf27ee230b50b55a09f33a0"
I (9686) HTTP: HTTP_EVENT_ON_HEADER, key=Access-Control-Allow-Origin, value=*
I (9686) HTTP: HTTP_EVENT_ON_HEADER, key=expiry_extended_seconds, value=0
I (9696) HTTP: HTTP_EVENT_ON_HEADER, key=Cache-Control, value=no-transform, max-age=120
I (9706) HTTP: HTTP_EVENT_ON_HEADER, key=Date, value=Tue, 10 Dec 2024 02:34:07 GMT
I (9716) HTTP: HTTP_EVENT_ON_HEADER, key=Content-Length, value=3545
I (9716) HTTP: HTTP_EVENT_ON_HEADER, key=Connection, value=keep-alive

Is that done via the esp_http_client_perform() function?

[nopnop2002]

Is that done via the esp_http_client_perform() function?

Yes.