grpc_mdelem *grpc_mdelem_from_string_and_buffer(grpc_mdctx *ctx,
const char *key,
const gpr_uint8 *value,
size_t value_length) {
return grpc_mdelem_from_metadata_strings(
ctx, grpc_mdstr_from_string(ctx, key),
grpc_mdstr_from_buffer(ctx, value, value_length));
}
static void hc_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
grpc_transport_stream_op *op) {
/* grab pointers to our data from the call element */
call_data *calld = elem->call_data;
channel_data *channeld = elem->channel_data;
if (op->send_initial_metadata != NULL) {
/* Decide which HTTP VERB to use. We use GET if the request is marked
cacheable, and the operation contains both initial metadata and send
message, and the payload is below the size threshold, and all the data
for this request is immediately available. */
grpc_mdelem *method = GRPC_MDELEM_METHOD_POST;
if ((op->send_initial_metadata_flags &
GRPC_INITIAL_METADATA_CACHEABLE_REQUEST) &&
op->send_message != NULL &&
op->send_message->length < channeld->max_payload_size_for_get) {
method = GRPC_MDELEM_METHOD_GET;
/* The following write to calld->send_message_blocked isn't racy with
reads in hc_start_transport_op (which deals with SEND_MESSAGE ops) because
being here means ops->send_message is not NULL, which is primarily
guarding the read there. */
calld->send_message_blocked = true;
} else if (op->send_initial_metadata_flags &
GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST) {
method = GRPC_MDELEM_METHOD_PUT;
}
/* Attempt to read the data from send_message and create a header field. */
if (method == GRPC_MDELEM_METHOD_GET) {
/* allocate memory to hold the entire payload */
calld->payload_bytes = gpr_malloc(op->send_message->length);
/* read slices of send_message and copy into payload_bytes */
calld->send_op = *op;
calld->send_length = op->send_message->length;
calld->send_flags = op->send_message->flags;
continue_send_message(exec_ctx, elem);
if (calld->send_message_blocked == false) {
/* when all the send_message data is available, then create a MDELEM and
append to headers */
grpc_mdelem *payload_bin = grpc_mdelem_from_metadata_strings(
GRPC_MDSTR_GRPC_PAYLOAD_BIN,
grpc_mdstr_from_buffer(calld->payload_bytes,
op->send_message->length));
grpc_metadata_batch_add_tail(op->send_initial_metadata,
&calld->payload_bin, payload_bin);
calld->on_complete = op->on_complete;
op->on_complete = &calld->hc_on_complete;
op->send_message = NULL;
} else {
/* Not all data is available. Fall back to POST. */
gpr_log(GPR_DEBUG,
"Request is marked Cacheable but not all data is available.\
Falling back to POST");
method = GRPC_MDELEM_METHOD_POST;
}
}
grpc_mdstr *grpc_mdstr_from_slice(grpc_mdctx *ctx, gpr_slice slice) {
grpc_mdstr *result = grpc_mdstr_from_buffer(ctx, GPR_SLICE_START_PTR(slice),
GPR_SLICE_LENGTH(slice));
gpr_slice_unref(slice);
return result;
}
grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str) {
return grpc_mdstr_from_buffer(ctx, (const gpr_uint8 *)str, strlen(str));
}
