Function esp_idf_svc::sys::httpd_req_get_hdr_value_str

pub unsafe extern "C" fn httpd_req_get_hdr_value_str(
    r: *mut httpd_req,
    field: *const i8,
    val: *mut i8,
    val_size: usize,
) -> i32

@brief Get the value string of a field from the request headers

@note

• This API is supposed to be called only from the context of a URI handler where httpd_req_t* request pointer is valid.
• Once httpd_resp_send() API is called all request headers are purged, so request headers need be copied into separate buffers if they are required later.
• If output size is greater than input, then the value is truncated, accompanied by truncation error as return value.
• Use httpd_req_get_hdr_value_len() to know the right buffer length

@param[in] r The request being responded to @param[in] field The field to be searched in the header @param[out] val Pointer to the buffer into which the value will be copied if the field is found @param[in] val_size Size of the user buffer “val”

@return

• ESP_OK : Field found in the request header and value string copied
• ESP_ERR_NOT_FOUND : Key not found
• ESP_ERR_INVALID_ARG : Null arguments
• ESP_ERR_HTTPD_INVALID_REQ : Invalid HTTP request pointer
• ESP_ERR_HTTPD_RESULT_TRUNC : Value string truncated