moonbridge

view reference.txt @ 306:25f40c8d5082

Added tag v1.0.2 for changeset e4e1ad8d5ab8
author jbe
date Sun Nov 19 02:21:26 2017 +0100 (2017-11-19)
parents ce109800ae2d
children 334ea1f13b0b
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() (in an infinite
88 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.catch_sigterm()
304 This function installs a signal handler for SIGTERM. Instead of causing
305 immediate process termination, the behavior of moonbridge_io.poll(...) is
306 modified.
308 See moonbridge_io.poll(...) for further information.
311 ### moonbridge_io.exec(command, arg1, arg2, ...)
313 Executes the given command and returns a child handle with three sockets named
314 "stdin", "stdout", and "stderr" as well as the following methods:
316 - :kill(signal)
317 - :wait()
318 - :wait_nb()
319 - :wait_call(waitfunc)
320 - :wait_yield()
322 Use :kill(signal) to terminate the process with the given signal (defaults to 9
323 for SIGKILL).
325 The :wait() method will wait for the process to terminate and return its exit
326 code. If the process was terminated by a signal, a negative integer is returned
327 which corresponds to the respective positive signal number.
329 The method :wait_nb() is the same as :wait(), except that it does not block but
330 returns false (plus a notice as second return value) if the child process has
331 not terminated yet.
333 The method :wait_call() is the same as :wait() but calls waitfunc() (in an
334 infinite loop) as long as the process is still running.
336 The method :wait_yield() is an alias for :wait_call(coroutine.yield).
338 It is possible to wait for process termination by including the child handle
339 in the input_set of the moonbridge_io.poll(...) call.
341 moonbridge_io.exec(...) returns nil (as first return value) plus an error
342 message (as second return value) in case of error.
345 ### moonbridge_io.getpid()
347 Returns the current PID.
350 ### moonbridge_io.localconnect(path)
352 Tries to connect to a local socket (also known as Unix Domain Socket). Returns
353 a socket object on success, or nil (as first return value) plus an error
354 message (as second return value) in case of error.
357 ### moonbridge_io.localconnect_nb(path)
359 Tries to connect to a local socket (also known as Unix Domain Socket). Returns
360 a socket object on success, or nil (as first return value) plus an error
361 message (as second return value) in case of error.
363 Same as moonbridge_io.localconnect(path), except that this function does not
364 block and immediately returns a socket object.
366 In case of an I/O error, nil (as first return value) plus an error message (as
367 second return value) may be returned. However, connection errors may also be
368 reported on first read or write on the socket.
371 ### moonbridge_io.locallisten(path)
373 Attempts to create a local socket (also known as Unix Domain Socket) to accept
374 incoming connections. If the file does already exist and is a socket, then it
375 is deleted automatically before being re-created.
377 In case of an I/O error, nil (as first return value) plus an error message (as
378 second return value) may be returned. On success, a listener object is returned
379 which supports the methods :accept(), :accept_nb(), and :close().
381 The method :accept() blocks until a new incoming connection is available, in
382 which case a socket object is returned.
384 The method :accept_nb() works like :accept(), except that the call is
385 nonblocking and returns false (plus a notice as second return value) in case no
386 incoming connection is available. It is possible to wait for an incoming
387 connection by including the listener object in the input_set of the
388 moonbridge_io.poll(...) call.
390 The method :close() will close the listening socket. In case of local sockets
391 (Unix Domain Sockets), the socket will not be unlinked in the file system.
393 I/O errors by the methods of the listener object are also reported by returning
394 nil (as first return value) plus an error message (as second return value).
397 ### moonbridge_io.poll(input_set, output_set, timeout, wakeup_on_sigterm)
399 This function waits for at least one of the given file descriptors and/or
400 I/O handles to be ready for input or output. The two sets of file descriptors
401 and/or handles must contain the file descriptor or handle as a key, and a value
402 which does evaluate to true, e.g. input_set = {[socketA] = true}. If a set is
403 nil, it is treated as being empty.
405 The input_set may also contain listeners (to wait for incoming connections) and
406 child handles (to wait for process termination).
408 If the 4th parameter (wakeup_on_sigterm) is set to true, then the function
409 returns immediately if the process received at least one SIGTERM signal after
410 moonbridge_io.catch_sigterm() has been called for the first time. Three values
411 are returned if a timeout happened or a SIGTERM has been received: false as
412 first return value, a message string as second return value (that may, for
413 example, be used for assert(...)), and a boolean as third return value which
414 indicates whether the function prematurely returned because of SIGTERM.
416 If the 4th parameter (wakeup_on_sigterm) is omitted or set to false, then the
417 function only returns false as first return value if a timeout happened. In
418 this case, the second return value also will be set to an appropriate message
419 string such that assert(moonbridge_io.poll(...)) can be used to throw an error.
421 In all other cases, the function returns true as a single return value. The
422 function may also return true (for technical reasons) if signals other than
423 SIGTERM have been received during waiting.
425 Note that the function is not thread-safe when the 4th parameter is set to
426 true.
429 ### moonbridge_io.tcpconnect(hostname, port)
431 Tries to open a TCP connection with the given host and TCP port number. Returns
432 a socket object on success, or nil (as first return value) plus an error
433 message (as second return value) in case of error.
436 ### moonbridge_io.tcpconnect_nb(hostname, port)
438 Same as moonbridge_io.tcpconnect(hostname, port), except that this function
439 does not block and immediately returns a socket object.
441 Note: The current implementation still blocks during the DNS lookup. Use a
442 numeric IP address as hostname to be truly nonblocking.
444 In case of an I/O error, nil (as first return value) plus an error message (as
445 second return value) may be returned. However, connection errors may also be
446 reported on first read or write on the socket.
449 ### moonbridge_io.tcplisten(hostname, port)
451 Attempts to open a TCP port for listening. To listen on the loopback interface,
452 use "::1" as hostname if IPv6 shall be used, or use "127.0.0.1" as hostname if
453 IPv4 shall be used. To listen on all available interfaces, use "::" (IPv6) or
454 "0.0.0.0" (IPv4) respectively.
456 In case of an I/O error, nil (as first return value) plus an error message (as
457 second return value) may be returned. On success, a listener object is returned
458 which supports the methods :accept(), :accept_nb(), and :close(). See reference
459 for moonbridge.io_locallisten(...).
462 ### moonbridge_io.timeref(previous)
464 Helper function which returns a time reference (in SI-seconds). If a value is
465 passed as an optional argument to the function, then that value is substracted
466 from the result. A common idiom is:
468 local starttime = moonbridge_io.timeref()
469 [...]
470 while true do
471 [...]
472 if not moonbridge_io.poll(
473 input_set,
474 output_set,
475 timeout - moonbridge_io.timeref(starttime)
476 ) then
477 error("Timeout")
478 end
479 [...]
480 end
484 HTTP module
485 -----------
487 The HTTP module exports the function moonbridge_http.generate_handler(callback)
488 that converts an HTTP handler to a "connect" handler. See file "helloworld.lua"
489 for a simple example or "example_application.lua" for a more complex example of
490 invocation. A table with options may be passed either as a second argument, or
491 as a first argument preceeding the callback function (whichever is more
492 convenient).
494 The following options are supported:
496 - request_body_size_limit: maximum size of payload of HTTP request body
497 (transfer encoding is allowed to add a limited amount of extra data)
498 - chunk_size: optional default value for maximum_input_chunk_size and
499 minimum_output_chunk_size
500 - request_header_size_limit: maximum size of HTTP request headers
501 - maximum_input_chunk_size: maximum chunk size when streaming a request body or
502 certain POST fields (bigger chunks will be fragmented automatically)
503 - minimum_output_chunk_size: minimum size for a chunk when sending a response
504 body (smaller chunks will be buffered and concatenated with future data;
505 ignored when request:flush() is called)
506 - static_headers: a set of headers to be included in every HTTP response
507 (may be a string, a table or strings, or a table of key-value pairs)
509 The callback function receives a single request object as argument, which is
510 described below.
513 ### request.body
515 The request body (without headers) as a string. Accessing this value makes
516 further access to request.post_params and request.post_params_list, or
517 invocation of request:stream_request_body(...) impossible.
520 ### request:close_after_finish()
522 Closes the connection after answering the request.
524 This method can only be called before the HTTP response header section has been
525 finished (i.e. before request:finish_headers(), request:send_data(...), or
526 request:finish() were called), but it may be called before a status code has
527 been sent using request:send_status(...).
529 A corresponding "Connection: close" header is automatically sent.
531 See also request:monologue().
534 ### request:consume_input()
536 Starts processing the request body (if existent) to set the values
537 request.post_params, request.post_params_list, request.post_metadata, and
538 and request.post_metadata_list and/or to call POST field stream handlers that
539 have been previously registered with request:stream_post_param(...) or
540 request:stream_post_params(...), or to call a previously registered request
541 body stream handler that was set with request:set_request_body_streamer().
543 This method gets invoked automatically when the POST param tables
544 (request.post_params, etc.) are accessed or if request.body is accessed.
547 ### request.cookies
549 A table with all cookies sent by the client.
552 ### request.faulty
554 Normally set to false. In case of a write error on the client connection or
555 certain other unexpected errors, this value is set to true before a Lua error
556 is raised.
558 A faulty request handle must not be used, or another Lua error will be raised.
561 ### request:finish()
563 Finishes and flushes a HTTP response. An HTTP status, all headers, and the
564 response body (if applicable) must have been previously sent. May be called
565 multiple times (performs no operation if called on a finished request handle).
566 Gets automatically invoked when the callback handler returns. After calling
567 this method explicitly, no further data may be written.
570 ### request:finish_headers()
572 Finishes and flushes the HTTP response header section. May be called multiple
573 times, as long as the request is not finished completely. This method is
574 automatically invoked if the application is beginning to send a response body.
575 After calling this method, no further headers may be sent.
578 ### request:flush()
580 Flushes any pending output data. Note: In order to mark the end of a response
581 body, it is required to call request:finish().
584 ### request.fresh
586 Set to false whenever the request object has been used (e.g. data has been read
587 or sent out, or a stream handler was installed); true otherwise.
590 ### request.get_params
592 A table that maps field names to their corresponding GET value. If there are
593 several GET values with the given field name, then the first value is used.
595 Note: May be implemented through metamethods, but does support iteration
596 through pairs(...).
599 ### request.get_params_list
601 A table that maps field names to a sequence of their corresponding GET values.
603 Note: May be implemented through metamethods, but does support iteration
604 through pairs(...).
607 ### request.headers
609 A table that maps (case-insensitively) a HTTP header field name to a sequence
610 of values. For each occurrence of the respective header line, a string entry is
611 created in that sequence. Non-existent headers are mapped to an empty table.
614 ### request.headers_csv_string
616 A table that maps (case-insensitively) a HTTP header field name to a comma
617 separated string. Multiple occurrences of the header with the given field name
618 are automatically merged into the comma separated string.
621 ### request.headers_csv_table
623 A table that maps (case-insensitively) a HTTP header field name to a sequence
624 of values. One entry is created in that sequence for every comma separated
625 value of each header with the given field name.
628 ### request.headers_flags
630 A table that maps (case-insensitively) a HTTP header field name to another
631 table which (again case-insensitively) maps a string to a boolean, depending on
632 whether this string occurred in the list of comma separated values of one
633 header line with the given field name that was the key in the first table.
636 ### request.headers_value
638 A table that maps (case-insensitively) a HTTP header field name to a value. If
639 multiple header lines with the given field name have been received, false is
640 used as value.
643 ### request.method
645 The HTTP request method, e.g. "HEAD", "GET", or "POST".
648 ### request:monologue()
650 Same as request:close_after_finish() but additionally discards all input data
651 immediately.
654 ### request.path
656 The requested path without a leading slash and without the query part (e.g.
657 "index.html" if "/index.html?a=b&c=d" has been requested). For the query part,
658 see request.query.
660 This value will be nil if (and only if) the request method is "OPTIONS" with a
661 request target equal to "*" (see also asterisk-form of request-target in
662 section 5.3.4 in RFC 7230).
665 ### request.post_metadata
667 Only set for multipart/form-data POST requests. A table that maps field names
668 to their corresponding POST metadata table which contains two entries:
669 "file_name" and "content_type". If there are several POST values with the given
670 field name, then the first value/file is used.
672 Note: May be implemented through metamethods, but does support iteration
673 through pairs(...).
676 ### request.post_metadata_list
678 Only set for multipart/form-data POST requests. A table that maps field names
679 to a sequence with their corresponding POST metadata tables. Needed if multiple
680 files are uploaded with the same field name.
682 Note: May be implemented through metamethods, but does support iteration
683 through pairs(...).
686 ### request.post_params
688 A table that maps field names to their corresponding POST value. If there are
689 several POST values with the given field name, then the first value is used.
691 Note: May be implemented through metamethods, but does support iteration
692 through pairs(...).
695 ### request.post_params_list
697 A table that maps field names to a sequence of their corresponding POST values.
699 Note: May be implemented through metamethods, but does support iteration
700 through pairs(...).
703 ### request.query
705 Query part of the request target including the leading question mark, e.g.
706 "?a=b&c=d" if the requested target is "/index.html?a=b&c=d". The data is
707 automatically parsed and made available through request.get_params and
708 request.get_params_list.
710 If there is no query part given in the request target, then this string is
711 the empty string. This value will be nil if (and only if) the request method
712 is "OPTIONS" with a request target equal to "*" (see also asterisk-form of
713 request-target in section 5.3.4 in RFC 7230).
716 ### request:send_data(...)
718 Sends data as response body. All arguments are converted via tostring(...) and
719 concatenated. May be called multiple times until the request has been finished
720 by calling request:finish().
722 If the request method (see request.method) is "HEAD", then calls to
723 request:send_data(...) are automatically ignored.
726 ### request:send_header(key, value)
728 Sends a HTTP response header that consists of the given key and the given
729 value. Note: Key and value must be provided as separate arguments. Before any
730 headers can be sent, a HTTP status must have been set with
731 request:send_status(status_string).
734 ### request:send_status(status_string)
736 Sends a HTTP response status that is given as a string consisting of a 3-digit
737 number and an explanatory string, e.g. "200 OK" or "404 Not Found". This
738 function must be called once before any headers or response body data may be
739 sent.
742 ### request.socket
744 The underlaying socket. Can be used to force a TCP RST, etc.
747 ### request:stream_post_param(field_name, callback)
749 Registers a stream handler for the given POST parameter. The callback function
750 will be called in the following manner:
752 - For the initial chunk, the first chunk gets passed as first argument while a
753 table with metadata ("field_name" and "content_type") gets passed as second
754 argument. In case of an immediate EOF (i.e. an empty file), the passed
755 chunk is the empty string. In all other cases the chunk has a length greater
756 than zero.
757 - For any remaining chunks, the respective chunk gets passed as first and only
758 argument (no metadata). Here, the chunk has always a length greater than
759 zero.
760 - To indicate the end of the stream, the callback function is called without
761 arguments. This also happens in case of an immediate EOF (see above).
763 In case of an immediate EOF (i.e. an empty file), the callback function is thus
764 called as follows:
766 - The first time with an empty string as first argument, and with the metadata
767 as second argument.
768 - The second time without any arguments.
770 Note that request:consume_input() needs to be called to enforce streaming to
771 finish.
774 ### request:stream_post_params(pattern, callback)
776 Same as request:stream_post_param(...) but providing a string pattern to match
777 multiple field names (e.g. "^file_[0-9]+$").
780 ### request:stream_request_body(callback)
782 Registeres a stream handler for the whole request body. For each chunk of the
783 request body, the callback function is called with the corresponding chunk. End
784 of data is indicated by passing a nil value to the callback functuion.
786 Note that request:consume_input() needs to be called to enforce streaming to
787 finish.
790 ### request:stream_request_body_now(callback)
792 Start streaming of request body immediately. On EOF the function returns and
793 the callback function is *not* called with nil as argument.

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