static write_state
on_write_chunk(struct ev_loop* mainloop, Request* request)
{
if (do_send_chunk(request))
// data left to send in the current chunk
return not_yet_done;
if(request->iterator) {
/* Reached the end of a chunk in the response iterator. Get next chunk. */
PyObject* next_chunk = wsgi_iterable_get_next_chunk(request);
if(next_chunk) {
/* We found another chunk to send. */
if(request->state.chunked_response) {
request->current_chunk = wrap_http_chunk_cruft_around(next_chunk);
Py_DECREF(next_chunk);
} else {
request->current_chunk = next_chunk;
}
assert(request->current_chunk_p == 0);
return not_yet_done;
} else {
if(PyErr_Occurred()) {
/* Trying to get the next chunk raised an exception. */
PyErr_Print();
DBG_REQ(request, "Exception in iterator, can not recover");
return aborted;
} else {
/* This was the last chunk; cleanup. */
Py_CLEAR(request->iterator);
goto send_terminator_chunk;
}
}
} else {
/* We have no iterator to get more chunks from, so we're done.
* Reasons we might end up in this place:
* A) A parse or server error occurred
* C) We just finished a chunked response with the call to 'do_send_chunk'
* above and now maybe have to send the terminating empty chunk.
* B) We used chunked responses earlier in the response and
* are now sending the terminating empty chunk.
*/
goto send_terminator_chunk;
}
assert(0); // unreachable
send_terminator_chunk:
if(request->state.chunked_response) {
/* We have to send a terminating empty chunk + \r\n */
request->current_chunk = PyString_FromString("0\r\n\r\n");
assert(request->current_chunk_p == 0);
// Next time we get here, don't send the terminating empty chunk again.
// XXX This is kind of a hack and should be refactored for easier understanding.
request->state.chunked_response = false;
return not_yet_done;
} else {
return done;
}
}
/* XXX too many gotos */
static void
ev_io_on_write(struct ev_loop* mainloop, ev_io* watcher, const int events)
{
Request* request = REQUEST_FROM_WATCHER(watcher);
GIL_LOCK(0);
if(request->state.use_sendfile) {
/* sendfile */
if(request->current_chunk) {
/* current_chunk contains the HTTP headers */
if(send_chunk(request))
goto out;
assert(!request->current_chunk_p);
/* abuse current_chunk_p to store the file fd */
request->current_chunk_p = PyObject_AsFileDescriptor(request->iterable);
goto out;
}
if(do_sendfile(request))
goto out;
} else {
/* iterable */
if(send_chunk(request))
goto out;
if(request->iterator) {
PyObject* next_chunk;
next_chunk = wsgi_iterable_get_next_chunk(request);
if(next_chunk) {
if(request->state.chunked_response) {
request->current_chunk = wrap_http_chunk_cruft_around(next_chunk);
Py_DECREF(next_chunk);
} else {
request->current_chunk = next_chunk;
}
assert(request->current_chunk_p == 0);
goto out;
} else {
if(PyErr_Occurred()) {
PyErr_Print();
/* We can't do anything graceful here because at least one
* chunk is already sent... just close the connection */
DBG_REQ(request, "Exception in iterator, can not recover");
ev_io_stop(mainloop, &request->ev_watcher);
close(request->client_fd);
Request_free(request);
goto out;
}
Py_CLEAR(request->iterator);
}
}
if(request->state.chunked_response) {
/* We have to send a terminating empty chunk + \r\n */
request->current_chunk = PyString_FromString("0\r\n\r\n");
assert(request->current_chunk_p == 0);
request->state.chunked_response = false;
goto out;
}
}
ev_io_stop(mainloop, &request->ev_watcher);
if(request->state.keep_alive) {
DBG_REQ(request, "done, keep-alive");
Request_clean(request);
Request_reset(request);
ev_io_init(&request->ev_watcher, &ev_io_on_read,
request->client_fd, EV_READ);
ev_io_start(mainloop, &request->ev_watcher);
} else {
DBG_REQ(request, "done, close");
close(request->client_fd);
Request_free(request);
}
out:
GIL_UNLOCK(0);
}
bool
wsgi_call_application(Request* request)
{
StartResponse* start_response = PyObject_NEW(StartResponse, &StartResponse_Type);
start_response->request = request;
/* From now on, `headers` stores the _response_ headers
* (passed by the WSGI app) rather than the _request_ headers */
PyObject* request_headers = request->headers;
request->headers = NULL;
/* application(environ, start_response) call */
PyObject* retval = PyObject_CallFunctionObjArgs(
request->server_info->wsgi_app,
request_headers,
start_response,
NULL /* sentinel */
);
Py_DECREF(request_headers);
Py_DECREF(start_response);
if(retval == NULL)
return false;
/* The following code is somewhat magic, so worth an explanation.
*
* If the application we called was a generator, we have to call .next() on
* it before we do anything else because that may execute code that
* invokes `start_response` (which might not have been invoked yet).
* Think of the following scenario:
*
* def app(environ, start_response):
* start_response('200 Ok', ...)
* yield 'Hello World'
*
* That would make `app` return an iterator (more precisely, a generator).
* Unfortunately, `start_response` wouldn't be called until the first item
* of that iterator is requested; `start_response` however has to be called
* _before_ the wsgi body is sent, because it passes the HTTP headers.
*
* If the application returned a list this would not be required of course,
* but special-handling is painful - especially in C - so here's one generic
* way to solve the problem:
*
* Look into the returned iterator in any case. This allows us to do other
* optimizations, for example if the returned value is a list with exactly
* one string in it, we can pick the string and throw away the list so bjoern
* does not have to come back again and look into the iterator a second time.
*/
PyObject* first_chunk;
if(PyList_Check(retval) && PyList_GET_SIZE(retval) == 1 &&
PyString_Check(PyList_GET_ITEM(retval, 0)))
{
/* Optimize the most common case, a single string in a list: */
PyObject* tmp = PyList_GET_ITEM(retval, 0);
Py_INCREF(tmp);
Py_DECREF(retval);
retval = tmp;
goto string; /* eeevil */
} else if(PyString_Check(retval)) {
/* According to PEP 333 strings should be handled like any other iterable,
* i.e. sending the response item for item. "item for item" means
* "char for char" if you have a string. -- I'm not that stupid. */
string:
if(PyString_GET_SIZE(retval)) {
first_chunk = retval;
} else {
Py_DECREF(retval);
first_chunk = NULL;
}
} else if(FileWrapper_CheckExact(retval)) {
request->state.use_sendfile = true;
request->iterable = ((FileWrapper*)retval)->file;
Py_INCREF(request->iterable);
Py_DECREF(retval);
request->iterator = NULL;
first_chunk = NULL;
} else {
/* Generic iterable (list of length != 1, generator, ...) */
request->iterable = retval;
request->iterator = PyObject_GetIter(retval);
if(request->iterator == NULL)
return false;
first_chunk = wsgi_iterable_get_next_chunk(request);
if(first_chunk == NULL && PyErr_Occurred())
return false;
}
if(request->headers == NULL) {
/* It is important that this check comes *after* the call to
* wsgi_iterable_get_next_chunk(), because in case the WSGI application
* was an iterator, there's no chance start_response could be called
* before. See above if you don't understand what I say. */
PyErr_SetString(
PyExc_RuntimeError,
"wsgi application returned before start_response was called"
);
Py_XDECREF(first_chunk);
return false;
}
/* keep-alive cruft */
if(http_should_keep_alive(&request->parser.parser)) {
if(request->state.response_length_unknown) {
if(request->parser.parser.http_major > 0 && request->parser.parser.http_minor > 0) {
/* On HTTP 1.1, we can use Transfer-Encoding: chunked. */
request->state.chunked_response = true;
request->state.keep_alive = true;
} else {
/* On HTTP 1.0, we can only resort to closing the connection. */
request->state.keep_alive = false;
}
} else {
/* We know the content-length. Can always keep-alive. */
request->state.keep_alive = true;
}
} else {
/* Explicit "Connection: close" (HTTP 1.1) or missing "Connection: keep-alive" (HTTP 1.0) */
request->state.keep_alive = false;
}
/* Get the headers and concatenate the first body chunk.
* In the first place this makes the code more simple because afterwards
* we can throw away the first chunk PyObject; but it also is an optimization:
* At least for small responses, the complete response could be sent with
* one send() call (in server.c:ev_io_on_write) which is a (tiny) performance
* booster because less kernel calls means less kernel call overhead. */
PyObject* buf = PyString_FromStringAndSize(NULL, 1024);
Py_ssize_t length = wsgi_getheaders(request, buf);
if(first_chunk == NULL) {
_PyString_Resize(&buf, length);
goto out;
}
if(request->state.chunked_response) {
PyObject* new_chunk = wrap_http_chunk_cruft_around(first_chunk);
Py_DECREF(first_chunk);
assert(PyString_GET_SIZE(new_chunk) >= PyString_GET_SIZE(first_chunk) + 5);
first_chunk = new_chunk;
}
assert(buf);
_PyString_Resize(&buf, length + PyString_GET_SIZE(first_chunk));
memcpy(PyString_AS_STRING(buf)+length, PyString_AS_STRING(first_chunk),
PyString_GET_SIZE(first_chunk));
Py_DECREF(first_chunk);
out:
request->state.wsgi_call_done = true;
request->current_chunk = buf;
request->current_chunk_p = 0;
return true;
}
static void io_write(Request* request)
{
//GIL_LOCK(0);
if(request->state.use_sendfile) {
dprint("发送文件给客户端");
/* sendfile */
if(request->current_chunk && send_chunk(request))
goto out;
/* abuse current_chunk_p to store the file fd */
request->current_chunk_p = PyObject_AsFileDescriptor(request->iterable);
if(do_sendfile(request))
goto out;
} else {
dprint("发送字符");
/* iterable */
if(send_chunk(request)){
dprint("一次发送即完成");
//uv_close((uv_handle_t*) &request->ev_watcher, _http_uv__on_close__cb);
goto out;
}
if(request->iterator) {
PyObject* next_chunk;
dprint("request迭代");
next_chunk = wsgi_iterable_get_next_chunk(request);
if(next_chunk) {
dprint("下一块chunk发送");
if(request->state.chunked_response) {
request->current_chunk = wrap_http_chunk_cruft_around(next_chunk);
Py_DECREF(next_chunk);
} else {
request->current_chunk = next_chunk;
}
assert(request->current_chunk_p == 0);
//io_write(request);
goto out;
} else {
if(PyErr_Occurred()) {
uv_err_t err;
dprint("迭代出错");
PyErr_Print();
DBG_REQ(request, "Exception in iterator, can not recover");
uv_close((uv_handle_t*) request->ev_watcher, on_close);
Request_free(request);
err = uv_last_error(loop);
UVERR(err, "uv_write error on next chunk");
ASSERT(0);
goto out;
}
dprint("没有下一块chunk");
Py_CLEAR(request->iterator);
}
}
if(request->state.chunked_response) {
dprint("如果是chunked_response 发送收尾数据,并置空chunked_response");
/* We have to send a terminating empty chunk + \r\n */
request->current_chunk = PyString_FromString("0\r\n\r\n");
assert(request->current_chunk_p == 0);
//io_write(request);
request->state.chunked_response = false;
goto out;
}
}
dprint("响应完成");
if(request->state.keep_alive) {
DBG_REQ(request, "done, keep-alive");
Request_clean(request);
Request_reset(request);
} else {
dprint("done not keep alive");
uv_close((uv_handle_t*) request->ev_watcher, on_close);
Request_free(request);
}
out:
dprint("本次字符发送结束");
//GIL_UNLOCK(0);
return;
}