moonbridge
view reference.txt @ 219:e53da349fd8f
Clarified nil/false return values of poll function and wait_nb method
| author | jbe |
|---|---|
| date | Tue Jun 23 02:10:59 2015 +0200 (2015-06-23) |
| parents | 35ea31e45b43 |
| children | 6c02564342fe |
line source
2 Moonbridge reference
3 ====================
7 Global function listen{...}
8 ---------------------------
10 This function initializes the Moonbridge Network Server. It may be called
11 multiple times. However, it is not allowed to register additional listeners by
12 calling listen(...) from a "prepare", "connect", or "finish" handler.
14 See file "example.lua" for parametrization of the listen(...) function.
16 Warning: Moonbridge will fork the Lua environment to handle parallel requests.
17 Functions provided as "prepare", "connect", and "finish" handlers may access
18 global variables, but for every child process these global variables will not
19 be shared! If you require a global state, a DBMS, cache server, or similar is
20 necessary.
24 Global function timeout(...)
25 ----------------------------
27 Calling this function with a positive number (time in seconds) sets a timer
28 that kills the current process after the selected time runs out. The remaining
29 time can be queried by calling this function without arguments.
31 Calling this function with a single argument that is the number zero will
32 disable the timeout.
34 Another mode of operation is selected by passing two arguments: a time (in
35 seconds) as first argument and a function as second argument. In this case, a
36 sub-timer will be used to limit the execution time of the function. In case of
37 timeout, the process will be killed (and the timeout function does not return).
38 If the time for the sub-timer is longer than a previously set timeout (using
39 the timeout(...) function with one argument), the shorter timeout (of the
40 previous call of timeout(...)) will have precedence.
42 Timers are also automatically reset (disabled) when a handler (prepare handler
43 or connect handler) returns. To shutdown processes after a certain time waiting
44 for a new request, use the idle_time parameter of the listen function.
48 Socket object passed to "connect" handler
49 -----------------------------------------
51 For every incoming connection, the registered "connect" handler is called with
52 a single socket object as argument, which is described below:
55 ### socket:close()
57 Closes the socket connection (input and output stream) by flushing all data and
58 sending a TCP FIN packet.
60 Returns true on success, or nil plus error message in case of an I/O error.
61 Using this method on sockets that have already been closed (or reset) will
62 throw an error.
64 Warning: Pending data on the input stream may cause connection aborts (TCP RST)
65 when network connections are used. All pending input data should have been read
66 (or drained) before calling socket:close(). Use socket:finish() to send a
67 TCP FIN packet to the peer before waiting for EOF from the peer.
69 A socket passed to the "connect" handler will be closed automatically if it was
70 not closed by the "connect" handler and if the "connect" handler returns
71 normally (i.e. without throwing an error). If the "connect" handler throws an
72 error, then the socket will be reset. See socket:reset().
75 ### socket:drain(maxlen, terminator)
77 Same as socket:read(maxlen, terminator), but discards the input and returns the
78 number of discarded bytes (as first return value) and the status code ("term",
79 "maxlen", "eof" as second return value).
81 In case of an I/O error, nil (as first return value) plus an error message (as
82 second return value) are returned.
85 ### socket:drain_call(waitfunc, maxlen, terminator)
87 Same as socket:drain(maxlen, terminator), but calls waitfunc(socket, "r") (in
88 an infinite loop) as long as the reading is blocked.
91 ### socket:drain_nb(maxlen, terminator)
93 Same as socket:drain(maxlen, terminator), but non-blocking. The status code
94 (which is returned as second return value) may therefore be "term", "maxlen",
95 "eof", or "block".
97 In case of an I/O error, nil (as first return value) plus an error message (as
98 second return value) are returned.
101 ### socket:drain_yield(maxlen, terminator)
103 Alias for socket:drain_call(coroutine.yield, maxlen, terminator)
106 ### socket:finish()
108 Sends a TCP FIN packet to indicate EOF on write stream. Subsequent reads are
109 still possible. When there is no more input data to be read, the connection
110 should finally be closed with socket:close().
112 In case of local sockets (Unix Domain Sockets), socket:finish() simply closes
113 the underlying socket and emulates EOF on subsequent reads. Also in this case,
114 the connection should be finally closed with socket:close().
117 ### socket:flush(...)
119 Same as socket:write(...) but additionally flushes the socket (i.e. all pending
120 data is passed to the operating system).
122 In case of an I/O error, nil (as first return value) plus an error message (as
123 second return value) are returned. On success, the socket userdata object is
124 returned.
127 ### socket:flush_call(waitfunc, ...)
129 Same as socket:flush(...), but calls waitfunc() (in an infinite loop) as long
130 as the writing is blocked.
133 ### socket:flush_nb(...)
135 Same as socket:write_nb(...) but additionally flushes the socket (i.e. all
136 pending data is passed to the operating system). The total number of bytes that
137 could not be passed yet to the operating system is returned. Zero is returned
138 if all data could be flushed out.
140 In case of an I/O error, nil (as first return value) plus an error message (as
141 second return value) are returned.
144 ### socket:flush_yield(...)
146 Alias for socket:flush_call(coroutine.yield, ...)
149 ### socket.interval
151 Set to the name of an interval timer if the "connect" handler was called due to
152 an elapsed interval timer. Otherwise nil.
155 ### socket.local_ip4
157 Local IPv4 address used for the connection. Encoded as 4 raw bytes in form of a
158 string.
161 ### socket.local_ip6
163 Local IPv6 address used for the connection. Encoded as 16 raw bytes in form of
164 a string.
167 ### socket.local_tcpport
169 Local TCP port used for the connection.
172 ### socket:read(maxlen, terminator)
174 Reads up to maxlen bytes or until an optional termination character is
175 encountered (which is included in the result). The maxlen value may be nil, in
176 which case there is no limit on the number of bytes read.
178 In case of an I/O error, nil (as first return value) plus an error message (as
179 second return value) are returned.
181 In all other cases (including EOF), the following two values are returned:
183 - a string containing the bytes read (first return value, may be empty string)
184 - a status code equal to "term", "maxlen", or "eof" (second return value)
186 If an EOF is encountered before all data could be read, then "eof" is returned
187 as second return value. If maxlen bytes have been read and no termination
188 character has been read, then "maxlen" is returned as second return value. If
189 the termination character is the last character of the read string, the second
190 return value will be "term".
193 ### socket:read_call(waitfunc, maxlen, terminator)
195 Same as socket:read(maxlen, terminator), but calls waitfunc() (in an infinite
196 loop) as long as the reading is blocked.
199 ### socket:read_nb(maxlen, terminator)
201 Same as socket:read(maxlen, terminator), but does not block.
203 In case of an I/O error, nil (as first return value) plus an error message (as
204 second return value) are returned.
206 In all other cases (including EOF), the following two values are returned:
208 - a string containing the bytes read (first return value, may be empty string)
209 - a status code equal to "term", "maxlen", "eof", "block" (second return value)
211 The status code "block" as second return value is used if the function returned
212 prematurely because it would block otherwise. In this case, the first return
213 value is a string that contains the bytes that could be read without blocking.
216 ### socket:read_yield(maxlen, terminator)
218 Alias for socket:read_call(coroutine.yield, maxlen, terminator)
221 ### socket.remote_ip4
223 Remote IPv4 address used for the connection. Encoded as 4 raw bytes in form of
224 a string.
227 ### socket.remote_ip6
229 Remote IPv6 address used for the connection. Encoded as 16 raw bytes in form of
230 a string.
233 ### socket.remote_tcpport
235 Remote TCP port used for the connection.
238 ### socket:reset()
240 Alias for socket:close(). Closes the socket connection by sending a TCP RST
241 packet if possible to indicate error condition. This is the default operation
242 when a socket handle gets garbage collected or the process is terminated
243 abnormally.
245 Returns true on success, or nil (as first return value) plus error message (as
246 second return value) in case of an I/O error. Using this method on sockets that
247 have already been closed (or reset) will throw an error.
249 Warning: Previously sent (and flushed) data may be lost during transmission.
252 ### socket:write(...)
254 Takes a variable number of strings and sends them to the peer. The operation is
255 buffered, so to actually send out the data, it is necessary to eventually call
256 socket:flush(), socket:finish(), or socket:close().
258 In case of an I/O error, nil (as first return value) plus an error message (as
259 second return value) are returned. On success, the socket userdata object is
260 returned.
263 ### socket:write_call(waitfunc, ...)
265 Same as socket:write(...), but calls waitfunc() (in an infinite loop) as long
266 as the writing is blocked.
269 ### socket:write_nb(...)
271 Takes a variable number of strings and sends them to the peer. The operation is
272 buffered, so to actually send out the data, it is necessary to eventually call
273 socket:flush_nb(), socket:flush(), socket:finish(), or socket:close().
275 This function always returns immediately (i.e. it does not block). If all data
276 (but a small buffered portion) could be sent out, then zero is returned.
277 Otherwise, all arguments that could not be sent are stored in a buffer of
278 unlimited size (up to memory capabilities) and an integer is returned that
279 indicates the number of bytes currently in the buffer.
281 In case of an I/O error, nil (as first return value) plus an error message (as
282 second return value) are returned.
285 ### socket:write_yield(...)
287 Alias for socket:write_call(coroutine.yield, ...)
291 I/O library
292 -----------
294 The Moonbridge Network Server for Lua Applications comes with its own I/O
295 library to support blocking as well as nonblocking I/O operations.
297 All methods on an I/O handle (e.g. socket) are described in the previous
298 section regarding the "socket" object. All other functions of the library are
299 listed below.
302 ### moonbridge_io.exec(command, arg1, arg2, ...)
304 Executes the given command and returns a handle with three sockets named
305 "stdin", "stdout", and "stderr" as well as the following methods:
307 - :kill(signal)
308 - :wait()
309 - :wait_nb()
310 - :wait_call(waitfunc)
311 - :wait_yield()
313 Use :kill(signal) to terminate the process with the given signal (defaults to
314 SIGTERM).
316 The :wait() method will wait for the process to terminate and return its exit
317 code. If the process was terminated by a signal, a negative integer is returned
318 which corresponds to the respective positive signal number.
320 The method :wait_nb() is the same as :wait(), except that it does not block but
321 returns false (plus a notice as second return value) if the child process has
322 not terminated yet.
324 The method :wait_call() is the same as :wait() but calls waitfunc() (in an
325 infinite loop) as long as the process is still running.
327 The method :wait_yield() is an alias for :wait_call(coroutine.yield).
330 ### moonbridge_io.localconnect(path)
332 Tries to connect to a local socket (also known as Unix Domain Socket). Returns
333 a socket object on success, or nil (as first return value) plus an error
334 message (as second return value) in case of error.
337 ### moonbridge_io.localconnect_nb(path)
339 Tries to connect to a local socket (also known as Unix Domain Socket). Returns
340 a socket object on success, or nil (as first return value) plus an error
341 message (as second return value) in case of error.
343 Same as moonbridge_io.localconnect(path), except that this function does not
344 block and immediately returns a socket object.
346 In case of an I/O error, nil (as first return value) plus an error message (as
347 second return value) may be returned. However, connection errors may also be
348 reported on first read or write on the socket.
351 ### moonbridge_io.locallisten(path)
353 Attempts to create a local socket (also known as Unix Domain Socket) to accept
354 incoming connections. If the file does already exist and is a socket, then it
355 is deleted automatically before being re-created.
357 In case of an I/O error, nil (as first return value) plus an error message (as
358 second return value) may be returned.On success, a listener object is returned
359 which supports the methods :accept(), :accept_nb(), and :close().
361 The method :accept() blocks until a new incoming connection is available in
362 which case a socket object is returned.
364 The method :accept_nb() works like :accept(), except that the call is
365 nonblocking and returns false (plus a notice as second return value) in case no
366 incoming connection is available. It is possible to wait for an incoming
367 connection by including the listener object in the input_set of the
368 moonbridge_io.poll(...) call.
370 The method :close() will close the listening socket. In case of local sockets
371 (Unix Domain Sockets), the socket will not be unlinked in the file system.
373 I/O errors by the methods of the listener object are also reported by returning
374 nil (as first return value) plus an error message (as second return value).
377 ### moonbridge_io.poll(input_set, output_set, timeout)
379 This function waits for at least one of the given file descriptors and/or
380 I/O handles to be ready for input or output. The two sets of file descriptors
381 and/or handles must contain the file descriptor or handle as a key, and a value
382 which does evaluate to true. If a set is nil, it is treated as being empty.
384 Returns true when at least one file descriptor or handle is ready for reading
385 or writing respectively. Returns false (plus a notice as second return value)
386 in case of timeout. Returns nil (plus a notice as second return value) if a
387 signal was received during waiting.
390 ### moonbridge_io.tcpconnect(hostname, port)
392 Tries to open a TCP connection with the given host and TCP port number. Returns
393 a socket object on success, or nil (as first return value) plus an error
394 message (as second return value) in case of error.
397 ### moonbridge_io.tcpconnect_nb(hostname, port)
399 Same as moonbridge_io.tcpconnect(hostname, port), except that this function
400 does not block and immediately returns a socket object.
402 Note: The current implementation still blocks during the DNS lookup. Use a
403 numeric IP address as hostname to be truly nonblocking.
405 In case of an I/O error, nil (as first return value) plus an error message (as
406 second return value) may be returned. However, connection errors may also be
407 reported on first read or write on the socket.
410 ### moonbridge_io.tcplisten(hostname, port)
412 Attempts to open a TCP port for listening. To listen on the loopback interface,
413 use "::1" as hostname if IPv6 shall be used, or use "127.0.0.1" as hostname if
414 IPv4 shall be used. To listen on all available interfaces, use "::" (IPv6) or
415 "0.0.0.0" (IPv4) respectively.
417 In case of an I/O error, nil (as first return value) plus an error message (as
418 second return value) may be returned. On success, a listener object is returned
419 which supports the methods :accept(), :accept_nb(), and :close(). See reference
420 for moonbridge.io_locallisten(...).
424 HTTP module
425 -----------
427 The http module exports the function http.generate_handler(callback) that
428 converts an HTTP handler to a "connect" handler. See file "example.lua" for an
429 example of invocation. A table with options may be passed either as a second
430 argument, or as a first argument preceeding the callback function (whichever is
431 more convenient).
433 The following options are supported:
435 - request_body_size_limit: maximum size of payload of HTTP request body
436 (transfer encoding is allowed to add a limited amount of extra data)
437 - chunk_size: optional default value for maximum_input_chunk_size and
438 minimum_output_chunk_size
439 - request_header_size_limit: maximum size of HTTP request headers
440 - maximum_input_chunk_size: maximum chunk size when streaming a request body or
441 certain POST fields (bigger chunks will be fragmented automatically)
442 - minimum_output_chunk_size: minimum size for a chunk when sending a response
443 body (smaller chunks will be buffered and concatenated with future data;
444 ignored when request:flush() is called)
445 - static_headers: a set of headers to be included in every HTTP response
446 (may be a string, a table or strings, or a table of key-value pairs)
448 The callback function receives a single request object as argument, which is
449 described below.
452 ### request.body
454 The request body (without headers) as a string. Accessing this value makes
455 further access to request.post_params and request.post_params_list, or
456 invocation of request:stream_request_body(...) impossible.
459 ### request:close_after_finish()
461 Closes the connection after answering the request.
463 This method can only be called before the HTTP response header section has been
464 finished (i.e. before request:finish_headers(), request:send_data(...), or
465 request:finish() were called), but it may be called before a status code has
466 been sent using request:send_status(...).
468 A corresponding "Connection: close" header is automatically sent.
470 See also request:monologue().
473 ### request:consume_input()
475 Starts processing the request body (if existent) to set the values
476 request.post_params, request.post_params_list, request.post_metadata, and
477 and request.post_metadata_list and/or to call POST field stream handlers that
478 have been previously registered with request:stream_post_param(...) or
479 request:stream_post_params(...), or to call a previously registered request
480 body stream handler that was set with request:set_request_body_streamer().
482 This method gets invoked automatically when the POST param tables
483 (request.post_params, etc.) are accessed or if request.body is accessed.
486 ### request.cookies
488 A table with all cookies sent by the client.
491 ### request.faulty
493 Normally set to false. In case of a write error on the client connection or
494 certain other unexpected errors, this value is set to true before a Lua error
495 is raised.
497 A faulty request handle must not be used, or another Lua error will be raised.
500 ### request:finish()
502 Finishes and flushes a HTTP response. May be called multiple times. An
503 HTTP status, all headers, and the response body (if applicable) must have been
504 previously sent. After calling this method, no further data may be written.
507 ### request:finish_headers()
509 Finishes and flushes the HTTP response header section. May be called multiple
510 times, as long as the request is not finished completely. This method is
511 automatically invoked if the application is beginning to send a response body.
512 After calling this method, no further headers may be sent.
515 ### request:flush()
517 Flushes any pending output data. Note: In order to mark the end of a response
518 body, it is required to call request:finish().
521 ### request.fresh
523 Set to false whenever the request object has been used (e.g. data has been read
524 or sent out, or a stream handler was installed); true otherwise.
527 ### request.get_params
529 A table that maps field names to their corresponding GET value. If there are
530 several GET values with the given field name, then the first value is used.
532 Note: May be implemented through metamethods, but does support iteration
533 through pairs(...).
536 ### request.get_params_list
538 A table that maps field names to a sequence of their corresponding GET values.
540 Note: May be implemented through metamethods, but does support iteration
541 through pairs(...).
544 ### request.headers
546 A table that maps (case-insensitively) a HTTP header field name to a sequence
547 of values. One entry is created for every occurrence of a header line with the
548 given field name).
551 ### request.headers_csv_string
553 A table that maps (case-insensitively) a HTTP header field name to a comma
554 separated string. Multiple occurrences of the header with the given field name
555 are automatically merged into the comma separated string.
558 ### request.headers_csv_table
560 A table that maps (case-insensitively) a HTTP header field name to a sequence
561 of values. One entry is created for every comma separated value of each header
562 with the given field name.
565 ### request.headers_flags
567 A table that maps (case-insensitively) a HTTP header field name to another
568 table which (again case-insensitively) maps a string to a boolean, depending on
569 whether this string occurred in the list of comma separated values of one
570 header line with the given field name that was the key in the first table.
573 ### request.headers_value
575 A table that maps (case-insensitively) a HTTP header field name to a value. If
576 multiple header lines with the given field name have been received, false is
577 used as value.
580 ### request.method
582 The HTTP request method, e.g. "HEAD", "GET", or "POST".
585 ### request:monologue()
587 Same as request:close_after_finish() but additionally discards all input data
588 immediately.
591 ### request.path
593 The requested path without a leading slash and without the query part (e.g.
594 "index.html" if "/index.html?a=b&c=d" has been requested). For the query part,
595 see request.query.
597 This value will be nil if (and only if) the request method is "OPTIONS" with a
598 request target equal to "*" (see also asterisk-form of request-target in
599 section 5.3.4 in RFC 7230).
602 ### request.post_metadata
604 Only set for multipart/form-data POST requests. A table that maps field names
605 to their corresponding POST metadata table which contains two entries:
606 "file_name" and "content_type". If there are several POST values with the given
607 field name, then the first value/file is used.
610 ### request.post_metadata_list
612 Only set for multipart/form-data POST requests. A table that maps field names
613 to a sequence with their corresponding POST metadata tables. Needed if multiple
614 files are uploaded with the same field name.
617 ### request.post_params
619 A table that maps field names to their corresponding POST value. If there are
620 several POST values with the given field name, then the first value is used.
622 Note: May be implemented through metamethods, but does support iteration
623 through pairs(...).
626 ### request.post_params_list
628 A table that maps field names to a sequence of their corresponding POST values.
630 Note: May be implemented through metamethods, but does support iteration
631 through pairs(...).
634 ### request.query
636 Query part of the request target including the leading question mark, e.g.
637 "?a=b&c=d" if the requested target is "/index.html?a=b&c=d". The data is
638 automatically parsed and made available through request.get_params and
639 request.get_params_list.
641 If there is no query part given in the request target, then this string is
642 the empty string. This value will be nil if (and only if) the request method
643 is "OPTIONS" with a request target equal to "*" (see also asterisk-form of
644 request-target in section 5.3.4 in RFC 7230).
647 ### request:send_data(...)
649 Sends data as response body. All arguments are converted via tostring(...) and
650 concatenated. May be called multiple times until the request has been finished
651 by calling request:finish().
653 If the request method (see request.method) is "HEAD", then calls to
654 request:send_data(...) are automatically ignored.
657 ### request:send_header(key, value)
659 Sends a HTTP response header that consists of the given key and the given
660 value. Note: Key and value must be provided as separate arguments. Before any
661 headers can be sent, a HTTP status must have been set with
662 request:send_status(status_string).
665 ### request:send_status(status_string)
667 Sends a HTTP response status that is given as a string consisting of a 3-digit
668 number and an explanatory string, e.g. "200 OK" or "404 Not Found". This
669 function must be called once before any headers or response body data may be
670 sent.
673 ### request.socket
675 The underlaying socket. Can be used to force a TCP RST, etc.
678 ### request:stream_post_param(field_name, callback)
680 Registers a stream handler for the given POST parameter. The callback function
681 will be called in the following manner:
683 - For the initial chunk, the first chunk gets passed as first argument while a
684 table with metadata ("field_name" and "content_type") gets passed as second
685 argument. In case of an immediate EOF (i.e. an empty file), the passed
686 chunk is the empty string. In all other cases the chunk has a length greater
687 than zero.
688 - For any remaining chunks, the respective chunk gets passed as first and only
689 argument (no metadata). Here, the chunk has always a length greater than
690 zero.
691 - To indicate the end of the stream, the callback function is called without
692 arguments. This also happens in case of an immediate EOF (see above).
694 In case of an immediate EOF (i.e. an empty file), the callback function is thus
695 called as follows:
697 - The first time with an empty string as first argument, and with the metadata
698 as second argument.
699 - The second time without any arguments.
701 Note that request:consume_input() needs to be called to enforce streaming to
702 finish.
705 ### request:stream_post_params(pattern, callback)
707 Same as request:stream_post_param(...) but providing a string pattern to match
708 multiple field names (e.g. "^file_[0-9]+$").
711 ### request:stream_request_body(callback)
713 Registeres a stream handler for the whole request body. For each chunk of the
714 request body, the callback function is called with the corresponding chunk. End
715 of data is indicated by passing a nil value to the callback functuion.
717 Note that request:consume_input() needs to be called to enforce streaming to
718 finish.
721 ### request:stream_request_body_now(callback)
723 Start streaming of request body immediately. On EOF the function returns and
724 the callback function is *not* called with nil as argument.
726 Note that request:consume_input() needs to be called to enforce streaming to
727 finish.