moonbridge
view reference.txt @ 281:6bb191b6ead5
Make :kill(signal) accept also strings and default to signal 9 (KILL); Improved error handling of :kill(signal)
| author | jbe |
|---|---|
| date | Thu Jun 08 01:52:18 2017 +0200 (2017-06-08) |
| parents | 1a4f89f4c712 |
| children | 28aab22e68b6 |
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.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 9
314 for SIGKILL).
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).
329 moonbridge_io.exec(...) returns nil (as first return value) plus an error
330 message (as second return value) in case of error.
333 ### moonbridge_io.localconnect(path)
335 Tries to connect to a local socket (also known as Unix Domain Socket). Returns
336 a socket object on success, or nil (as first return value) plus an error
337 message (as second return value) in case of error.
340 ### moonbridge_io.localconnect_nb(path)
342 Tries to connect to a local socket (also known as Unix Domain Socket). Returns
343 a socket object on success, or nil (as first return value) plus an error
344 message (as second return value) in case of error.
346 Same as moonbridge_io.localconnect(path), except that this function does not
347 block and immediately returns a socket object.
349 In case of an I/O error, nil (as first return value) plus an error message (as
350 second return value) may be returned. However, connection errors may also be
351 reported on first read or write on the socket.
354 ### moonbridge_io.locallisten(path)
356 Attempts to create a local socket (also known as Unix Domain Socket) to accept
357 incoming connections. If the file does already exist and is a socket, then it
358 is deleted automatically before being re-created.
360 In case of an I/O error, nil (as first return value) plus an error message (as
361 second return value) may be returned. On success, a listener object is returned
362 which supports the methods :accept(), :accept_nb(), and :close().
364 The method :accept() blocks until a new incoming connection is available, in
365 which case a socket object is returned.
367 The method :accept_nb() works like :accept(), except that the call is
368 nonblocking and returns false (plus a notice as second return value) in case no
369 incoming connection is available. It is possible to wait for an incoming
370 connection by including the listener object in the input_set of the
371 moonbridge_io.poll(...) call.
373 The method :close() will close the listening socket. In case of local sockets
374 (Unix Domain Sockets), the socket will not be unlinked in the file system.
376 I/O errors by the methods of the listener object are also reported by returning
377 nil (as first return value) plus an error message (as second return value).
380 ### moonbridge_io.poll(input_set, output_set, timeout)
382 This function waits for at least one of the given file descriptors and/or
383 I/O handles to be ready for input or output. The two sets of file descriptors
384 and/or handles must contain the file descriptor or handle as a key, and a value
385 which does evaluate to true, e.g. input_set = {[socketA] = true}. If a set is
386 nil, it is treated as being empty.
388 Returns true when at least one file descriptor or handle is ready for reading
389 or writing respectively, or if a signal has been received during waiting.
390 Returns false (plus a notice as second return value) in case of timeout.
393 ### moonbridge_io.signals
395 A table mapping a string (e.g. "TERM" or "KILL") to the corresponding signal
396 number (e.g. 9 or 15, respectively).
399 ### moonbridge_io.signalsocket(signal)
401 This function installs a signal handler. As argument, either the signal number
402 is passed (e.g. 15) or a name (e.g. "TERM"). The function returns a socket
403 object that receives a character (".") each time a signal is received.
405 The function can be called multiple times, in which case the same socket object
406 is returned. The returned socket should never be closed by the caller.
408 The process should not be forked after calling this function (except for
409 replacing the process with another program).
412 ### moonbridge_io.tcpconnect(hostname, port)
414 Tries to open a TCP connection with the given host and TCP port number. Returns
415 a socket object on success, or nil (as first return value) plus an error
416 message (as second return value) in case of error.
419 ### moonbridge_io.tcpconnect_nb(hostname, port)
421 Same as moonbridge_io.tcpconnect(hostname, port), except that this function
422 does not block and immediately returns a socket object.
424 Note: The current implementation still blocks during the DNS lookup. Use a
425 numeric IP address as hostname to be truly nonblocking.
427 In case of an I/O error, nil (as first return value) plus an error message (as
428 second return value) may be returned. However, connection errors may also be
429 reported on first read or write on the socket.
432 ### moonbridge_io.tcplisten(hostname, port)
434 Attempts to open a TCP port for listening. To listen on the loopback interface,
435 use "::1" as hostname if IPv6 shall be used, or use "127.0.0.1" as hostname if
436 IPv4 shall be used. To listen on all available interfaces, use "::" (IPv6) or
437 "0.0.0.0" (IPv4) respectively.
439 In case of an I/O error, nil (as first return value) plus an error message (as
440 second return value) may be returned. On success, a listener object is returned
441 which supports the methods :accept(), :accept_nb(), and :close(). See reference
442 for moonbridge.io_locallisten(...).
445 ### moonbridge_io.timeref(previous)
447 Helper function which returns a time reference (in SI-seconds). If a value is
448 passed as an optional argument to the function, then that value is substracted
449 from the result. A common idiom is:
451 local starttime = moonbridge_io.timeref()
452 [...]
453 while true do
454 [...]
455 if not moonbridge_io.poll(
456 input_set,
457 output_set,
458 timeout - moonbridge_io.timeref(starttime)
459 ) then
460 error("Timeout")
461 end
462 [...]
463 end
467 HTTP module
468 -----------
470 The HTTP module exports the function moonbridge_http.generate_handler(callback)
471 that converts an HTTP handler to a "connect" handler. See file "helloworld.lua"
472 for a simple example or "example_application.lua" for a more complex example of
473 invocation. A table with options may be passed either as a second argument, or
474 as a first argument preceeding the callback function (whichever is more
475 convenient).
477 The following options are supported:
479 - request_body_size_limit: maximum size of payload of HTTP request body
480 (transfer encoding is allowed to add a limited amount of extra data)
481 - chunk_size: optional default value for maximum_input_chunk_size and
482 minimum_output_chunk_size
483 - request_header_size_limit: maximum size of HTTP request headers
484 - maximum_input_chunk_size: maximum chunk size when streaming a request body or
485 certain POST fields (bigger chunks will be fragmented automatically)
486 - minimum_output_chunk_size: minimum size for a chunk when sending a response
487 body (smaller chunks will be buffered and concatenated with future data;
488 ignored when request:flush() is called)
489 - static_headers: a set of headers to be included in every HTTP response
490 (may be a string, a table or strings, or a table of key-value pairs)
492 The callback function receives a single request object as argument, which is
493 described below.
496 ### request.body
498 The request body (without headers) as a string. Accessing this value makes
499 further access to request.post_params and request.post_params_list, or
500 invocation of request:stream_request_body(...) impossible.
503 ### request:close_after_finish()
505 Closes the connection after answering the request.
507 This method can only be called before the HTTP response header section has been
508 finished (i.e. before request:finish_headers(), request:send_data(...), or
509 request:finish() were called), but it may be called before a status code has
510 been sent using request:send_status(...).
512 A corresponding "Connection: close" header is automatically sent.
514 See also request:monologue().
517 ### request:consume_input()
519 Starts processing the request body (if existent) to set the values
520 request.post_params, request.post_params_list, request.post_metadata, and
521 and request.post_metadata_list and/or to call POST field stream handlers that
522 have been previously registered with request:stream_post_param(...) or
523 request:stream_post_params(...), or to call a previously registered request
524 body stream handler that was set with request:set_request_body_streamer().
526 This method gets invoked automatically when the POST param tables
527 (request.post_params, etc.) are accessed or if request.body is accessed.
530 ### request.cookies
532 A table with all cookies sent by the client.
535 ### request.faulty
537 Normally set to false. In case of a write error on the client connection or
538 certain other unexpected errors, this value is set to true before a Lua error
539 is raised.
541 A faulty request handle must not be used, or another Lua error will be raised.
544 ### request:finish()
546 Finishes and flushes a HTTP response. An HTTP status, all headers, and the
547 response body (if applicable) must have been previously sent. May be called
548 multiple times (performs no operation if called on a finished request handle).
549 Gets automatically invoked when the callback handler returns. After calling
550 this method explicitly, no further data may be written.
553 ### request:finish_headers()
555 Finishes and flushes the HTTP response header section. May be called multiple
556 times, as long as the request is not finished completely. This method is
557 automatically invoked if the application is beginning to send a response body.
558 After calling this method, no further headers may be sent.
561 ### request:flush()
563 Flushes any pending output data. Note: In order to mark the end of a response
564 body, it is required to call request:finish().
567 ### request.fresh
569 Set to false whenever the request object has been used (e.g. data has been read
570 or sent out, or a stream handler was installed); true otherwise.
573 ### request.get_params
575 A table that maps field names to their corresponding GET value. If there are
576 several GET values with the given field name, then the first value is used.
578 Note: May be implemented through metamethods, but does support iteration
579 through pairs(...).
582 ### request.get_params_list
584 A table that maps field names to a sequence of their corresponding GET values.
586 Note: May be implemented through metamethods, but does support iteration
587 through pairs(...).
590 ### request.headers
592 A table that maps (case-insensitively) a HTTP header field name to a sequence
593 of values. For each occurrence of the respective header line, a string entry is
594 created in that sequence. Non-existent headers are mapped to an empty table.
597 ### request.headers_csv_string
599 A table that maps (case-insensitively) a HTTP header field name to a comma
600 separated string. Multiple occurrences of the header with the given field name
601 are automatically merged into the comma separated string.
604 ### request.headers_csv_table
606 A table that maps (case-insensitively) a HTTP header field name to a sequence
607 of values. One entry is created in that sequence for every comma separated
608 value of each header with the given field name.
611 ### request.headers_flags
613 A table that maps (case-insensitively) a HTTP header field name to another
614 table which (again case-insensitively) maps a string to a boolean, depending on
615 whether this string occurred in the list of comma separated values of one
616 header line with the given field name that was the key in the first table.
619 ### request.headers_value
621 A table that maps (case-insensitively) a HTTP header field name to a value. If
622 multiple header lines with the given field name have been received, false is
623 used as value.
626 ### request.method
628 The HTTP request method, e.g. "HEAD", "GET", or "POST".
631 ### request:monologue()
633 Same as request:close_after_finish() but additionally discards all input data
634 immediately.
637 ### request.path
639 The requested path without a leading slash and without the query part (e.g.
640 "index.html" if "/index.html?a=b&c=d" has been requested). For the query part,
641 see request.query.
643 This value will be nil if (and only if) the request method is "OPTIONS" with a
644 request target equal to "*" (see also asterisk-form of request-target in
645 section 5.3.4 in RFC 7230).
648 ### request.post_metadata
650 Only set for multipart/form-data POST requests. A table that maps field names
651 to their corresponding POST metadata table which contains two entries:
652 "file_name" and "content_type". If there are several POST values with the given
653 field name, then the first value/file is used.
655 Note: May be implemented through metamethods, but does support iteration
656 through pairs(...).
659 ### request.post_metadata_list
661 Only set for multipart/form-data POST requests. A table that maps field names
662 to a sequence with their corresponding POST metadata tables. Needed if multiple
663 files are uploaded with the same field name.
665 Note: May be implemented through metamethods, but does support iteration
666 through pairs(...).
669 ### request.post_params
671 A table that maps field names to their corresponding POST value. If there are
672 several POST values with the given field name, then the first value is used.
674 Note: May be implemented through metamethods, but does support iteration
675 through pairs(...).
678 ### request.post_params_list
680 A table that maps field names to a sequence of their corresponding POST values.
682 Note: May be implemented through metamethods, but does support iteration
683 through pairs(...).
686 ### request.query
688 Query part of the request target including the leading question mark, e.g.
689 "?a=b&c=d" if the requested target is "/index.html?a=b&c=d". The data is
690 automatically parsed and made available through request.get_params and
691 request.get_params_list.
693 If there is no query part given in the request target, then this string is
694 the empty string. This value will be nil if (and only if) the request method
695 is "OPTIONS" with a request target equal to "*" (see also asterisk-form of
696 request-target in section 5.3.4 in RFC 7230).
699 ### request:send_data(...)
701 Sends data as response body. All arguments are converted via tostring(...) and
702 concatenated. May be called multiple times until the request has been finished
703 by calling request:finish().
705 If the request method (see request.method) is "HEAD", then calls to
706 request:send_data(...) are automatically ignored.
709 ### request:send_header(key, value)
711 Sends a HTTP response header that consists of the given key and the given
712 value. Note: Key and value must be provided as separate arguments. Before any
713 headers can be sent, a HTTP status must have been set with
714 request:send_status(status_string).
717 ### request:send_status(status_string)
719 Sends a HTTP response status that is given as a string consisting of a 3-digit
720 number and an explanatory string, e.g. "200 OK" or "404 Not Found". This
721 function must be called once before any headers or response body data may be
722 sent.
725 ### request.socket
727 The underlaying socket. Can be used to force a TCP RST, etc.
730 ### request:stream_post_param(field_name, callback)
732 Registers a stream handler for the given POST parameter. The callback function
733 will be called in the following manner:
735 - For the initial chunk, the first chunk gets passed as first argument while a
736 table with metadata ("field_name" and "content_type") gets passed as second
737 argument. In case of an immediate EOF (i.e. an empty file), the passed
738 chunk is the empty string. In all other cases the chunk has a length greater
739 than zero.
740 - For any remaining chunks, the respective chunk gets passed as first and only
741 argument (no metadata). Here, the chunk has always a length greater than
742 zero.
743 - To indicate the end of the stream, the callback function is called without
744 arguments. This also happens in case of an immediate EOF (see above).
746 In case of an immediate EOF (i.e. an empty file), the callback function is thus
747 called as follows:
749 - The first time with an empty string as first argument, and with the metadata
750 as second argument.
751 - The second time without any arguments.
753 Note that request:consume_input() needs to be called to enforce streaming to
754 finish.
757 ### request:stream_post_params(pattern, callback)
759 Same as request:stream_post_param(...) but providing a string pattern to match
760 multiple field names (e.g. "^file_[0-9]+$").
763 ### request:stream_request_body(callback)
765 Registeres a stream handler for the whole request body. For each chunk of the
766 request body, the callback function is called with the corresponding chunk. End
767 of data is indicated by passing a nil value to the callback functuion.
769 Note that request:consume_input() needs to be called to enforce streaming to
770 finish.
773 ### request:stream_request_body_now(callback)
775 Start streaming of request body immediately. On EOF the function returns and
776 the callback function is *not* called with nil as argument.