moonbridge
view reference.txt @ 226:f132dc5b5bb0
Bugfix in error handling regarding broken client connection
| author | jbe |
|---|---|
| date | Sun Jul 12 18:59:51 2015 +0200 (2015-07-12) |
| parents | 828e2bca2e16 |
| children | 8593a1f2c15d |
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 15 for 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, e.g. input_set = {[socketA] = true}. If a set is
383 nil, it is treated as being empty.
385 Returns true when at least one file descriptor or handle is ready for reading
386 or writing respectively. Returns false (plus a notice as second return value)
387 in case of timeout. Returns nil (plus a notice as second return value) if a
388 signal was received during waiting.
391 ### moonbridge_io.tcpconnect(hostname, port)
393 Tries to open a TCP connection with the given host and TCP port number. Returns
394 a socket object on success, or nil (as first return value) plus an error
395 message (as second return value) in case of error.
398 ### moonbridge_io.tcpconnect_nb(hostname, port)
400 Same as moonbridge_io.tcpconnect(hostname, port), except that this function
401 does not block and immediately returns a socket object.
403 Note: The current implementation still blocks during the DNS lookup. Use a
404 numeric IP address as hostname to be truly nonblocking.
406 In case of an I/O error, nil (as first return value) plus an error message (as
407 second return value) may be returned. However, connection errors may also be
408 reported on first read or write on the socket.
411 ### moonbridge_io.tcplisten(hostname, port)
413 Attempts to open a TCP port for listening. To listen on the loopback interface,
414 use "::1" as hostname if IPv6 shall be used, or use "127.0.0.1" as hostname if
415 IPv4 shall be used. To listen on all available interfaces, use "::" (IPv6) or
416 "0.0.0.0" (IPv4) respectively.
418 In case of an I/O error, nil (as first return value) plus an error message (as
419 second return value) may be returned. On success, a listener object is returned
420 which supports the methods :accept(), :accept_nb(), and :close(). See reference
421 for moonbridge.io_locallisten(...).
425 HTTP module
426 -----------
428 The HTTP module exports the function moonbridge_http.generate_handler(callback)
429 that converts an HTTP handler to a "connect" handler. See file "helloworld.lua"
430 for a simple example or "example_application.lua" for a more complex example of
431 invocation. A table with options may be passed either as a second argument, or
432 as a first argument preceeding the callback function (whichever is more
433 convenient).
435 The following options are supported:
437 - request_body_size_limit: maximum size of payload of HTTP request body
438 (transfer encoding is allowed to add a limited amount of extra data)
439 - chunk_size: optional default value for maximum_input_chunk_size and
440 minimum_output_chunk_size
441 - request_header_size_limit: maximum size of HTTP request headers
442 - maximum_input_chunk_size: maximum chunk size when streaming a request body or
443 certain POST fields (bigger chunks will be fragmented automatically)
444 - minimum_output_chunk_size: minimum size for a chunk when sending a response
445 body (smaller chunks will be buffered and concatenated with future data;
446 ignored when request:flush() is called)
447 - static_headers: a set of headers to be included in every HTTP response
448 (may be a string, a table or strings, or a table of key-value pairs)
450 The callback function receives a single request object as argument, which is
451 described below.
454 ### request.body
456 The request body (without headers) as a string. Accessing this value makes
457 further access to request.post_params and request.post_params_list, or
458 invocation of request:stream_request_body(...) impossible.
461 ### request:close_after_finish()
463 Closes the connection after answering the request.
465 This method can only be called before the HTTP response header section has been
466 finished (i.e. before request:finish_headers(), request:send_data(...), or
467 request:finish() were called), but it may be called before a status code has
468 been sent using request:send_status(...).
470 A corresponding "Connection: close" header is automatically sent.
472 See also request:monologue().
475 ### request:consume_input()
477 Starts processing the request body (if existent) to set the values
478 request.post_params, request.post_params_list, request.post_metadata, and
479 and request.post_metadata_list and/or to call POST field stream handlers that
480 have been previously registered with request:stream_post_param(...) or
481 request:stream_post_params(...), or to call a previously registered request
482 body stream handler that was set with request:set_request_body_streamer().
484 This method gets invoked automatically when the POST param tables
485 (request.post_params, etc.) are accessed or if request.body is accessed.
488 ### request.cookies
490 A table with all cookies sent by the client.
493 ### request.faulty
495 Normally set to false. In case of a write error on the client connection or
496 certain other unexpected errors, this value is set to true before a Lua error
497 is raised.
499 A faulty request handle must not be used, or another Lua error will be raised.
502 ### request:finish()
504 Finishes and flushes a HTTP response. An HTTP status, all headers, and the
505 response body (if applicable) must have been previously sent. May be called
506 multiple times (performs no operation if called on a finished request handle).
507 Gets automatically invoked when the callback handler returns. After calling
508 this method explicitly, no further data may be written.
511 ### request:finish_headers()
513 Finishes and flushes the HTTP response header section. May be called multiple
514 times, as long as the request is not finished completely. This method is
515 automatically invoked if the application is beginning to send a response body.
516 After calling this method, no further headers may be sent.
519 ### request:flush()
521 Flushes any pending output data. Note: In order to mark the end of a response
522 body, it is required to call request:finish().
525 ### request.fresh
527 Set to false whenever the request object has been used (e.g. data has been read
528 or sent out, or a stream handler was installed); true otherwise.
531 ### request.get_params
533 A table that maps field names to their corresponding GET value. If there are
534 several GET values with the given field name, then the first value is used.
536 Note: May be implemented through metamethods, but does support iteration
537 through pairs(...).
540 ### request.get_params_list
542 A table that maps field names to a sequence of their corresponding GET values.
544 Note: May be implemented through metamethods, but does support iteration
545 through pairs(...).
548 ### request.headers
550 A table that maps (case-insensitively) a HTTP header field name to a sequence
551 of values. For each occurrence of the respective header line, a string entry is
552 created in that sequence. Non-existent headers are mapped to an empty table.
555 ### request.headers_csv_string
557 A table that maps (case-insensitively) a HTTP header field name to a comma
558 separated string. Multiple occurrences of the header with the given field name
559 are automatically merged into the comma separated string.
562 ### request.headers_csv_table
564 A table that maps (case-insensitively) a HTTP header field name to a sequence
565 of values. One entry is created in that sequence for every comma separated
566 value of each header with the given field name.
569 ### request.headers_flags
571 A table that maps (case-insensitively) a HTTP header field name to another
572 table which (again case-insensitively) maps a string to a boolean, depending on
573 whether this string occurred in the list of comma separated values of one
574 header line with the given field name that was the key in the first table.
577 ### request.headers_value
579 A table that maps (case-insensitively) a HTTP header field name to a value. If
580 multiple header lines with the given field name have been received, false is
581 used as value.
584 ### request.method
586 The HTTP request method, e.g. "HEAD", "GET", or "POST".
589 ### request:monologue()
591 Same as request:close_after_finish() but additionally discards all input data
592 immediately.
595 ### request.path
597 The requested path without a leading slash and without the query part (e.g.
598 "index.html" if "/index.html?a=b&c=d" has been requested). For the query part,
599 see request.query.
601 This value will be nil if (and only if) the request method is "OPTIONS" with a
602 request target equal to "*" (see also asterisk-form of request-target in
603 section 5.3.4 in RFC 7230).
606 ### request.post_metadata
608 Only set for multipart/form-data POST requests. A table that maps field names
609 to their corresponding POST metadata table which contains two entries:
610 "file_name" and "content_type". If there are several POST values with the given
611 field name, then the first value/file is used.
613 Note: May be implemented through metamethods, but does support iteration
614 through pairs(...).
617 ### request.post_metadata_list
619 Only set for multipart/form-data POST requests. A table that maps field names
620 to a sequence with their corresponding POST metadata tables. Needed if multiple
621 files are uploaded with the same field name.
623 Note: May be implemented through metamethods, but does support iteration
624 through pairs(...).
627 ### request.post_params
629 A table that maps field names to their corresponding POST value. If there are
630 several POST values with the given field name, then the first value is used.
632 Note: May be implemented through metamethods, but does support iteration
633 through pairs(...).
636 ### request.post_params_list
638 A table that maps field names to a sequence of their corresponding POST values.
640 Note: May be implemented through metamethods, but does support iteration
641 through pairs(...).
644 ### request.query
646 Query part of the request target including the leading question mark, e.g.
647 "?a=b&c=d" if the requested target is "/index.html?a=b&c=d". The data is
648 automatically parsed and made available through request.get_params and
649 request.get_params_list.
651 If there is no query part given in the request target, then this string is
652 the empty string. This value will be nil if (and only if) the request method
653 is "OPTIONS" with a request target equal to "*" (see also asterisk-form of
654 request-target in section 5.3.4 in RFC 7230).
657 ### request:send_data(...)
659 Sends data as response body. All arguments are converted via tostring(...) and
660 concatenated. May be called multiple times until the request has been finished
661 by calling request:finish().
663 If the request method (see request.method) is "HEAD", then calls to
664 request:send_data(...) are automatically ignored.
667 ### request:send_header(key, value)
669 Sends a HTTP response header that consists of the given key and the given
670 value. Note: Key and value must be provided as separate arguments. Before any
671 headers can be sent, a HTTP status must have been set with
672 request:send_status(status_string).
675 ### request:send_status(status_string)
677 Sends a HTTP response status that is given as a string consisting of a 3-digit
678 number and an explanatory string, e.g. "200 OK" or "404 Not Found". This
679 function must be called once before any headers or response body data may be
680 sent.
683 ### request.socket
685 The underlaying socket. Can be used to force a TCP RST, etc.
688 ### request:stream_post_param(field_name, callback)
690 Registers a stream handler for the given POST parameter. The callback function
691 will be called in the following manner:
693 - For the initial chunk, the first chunk gets passed as first argument while a
694 table with metadata ("field_name" and "content_type") gets passed as second
695 argument. In case of an immediate EOF (i.e. an empty file), the passed
696 chunk is the empty string. In all other cases the chunk has a length greater
697 than zero.
698 - For any remaining chunks, the respective chunk gets passed as first and only
699 argument (no metadata). Here, the chunk has always a length greater than
700 zero.
701 - To indicate the end of the stream, the callback function is called without
702 arguments. This also happens in case of an immediate EOF (see above).
704 In case of an immediate EOF (i.e. an empty file), the callback function is thus
705 called as follows:
707 - The first time with an empty string as first argument, and with the metadata
708 as second argument.
709 - The second time without any arguments.
711 Note that request:consume_input() needs to be called to enforce streaming to
712 finish.
715 ### request:stream_post_params(pattern, callback)
717 Same as request:stream_post_param(...) but providing a string pattern to match
718 multiple field names (e.g. "^file_[0-9]+$").
721 ### request:stream_request_body(callback)
723 Registeres a stream handler for the whole request body. For each chunk of the
724 request body, the callback function is called with the corresponding chunk. End
725 of data is indicated by passing a nil value to the callback functuion.
727 Note that request:consume_input() needs to be called to enforce streaming to
728 finish.
731 ### request:stream_request_body_now(callback)
733 Start streaming of request body immediately. On EOF the function returns and
734 the callback function is *not* called with nil as argument.