moonbridge
view reference.txt @ 143:41da87a681d6
Method "read" always returns two return values
| author | jbe |
|---|---|
| date | Sat May 02 01:48:29 2015 +0200 (2015-05-02) |
| parents | 9ca22af4d4b1 |
| children | e7fac0918f9c |
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.
70 ### socket:drain(maxlen, terminator)
72 Same as socket:read(maxlen, terminator), but discards the input and returns the
73 number of discarded bytes (as first return value) and the status code ("term",
74 "maxlen", "eof" as second return value).
76 In case of an I/O error, nil (as first return value) plus an error message (as
77 second return value) are returned.
80 ### socket:drain_nb(maxlen, terminator)
82 Same as socket:drain(maxlen, terminator), but non-blocking. The status code
83 (which is returned as second return value) may therefore be "term", "maxlen",
84 "eof", or "block".
86 In case of an I/O error, nil (as first return value) plus an error message (as
87 second return value) are returned.
90 ### socket:finish()
92 Sends a TCP FIN packet to indicate EOF on write stream. Subsequent reads are
93 still possible. When there is no more input data to be read, the connection
94 should finally be closed with socket:close().
96 In case of local sockets (Unix Domain Sockets), socket:finish() simply closes
97 the underlying socket and emulates EOF on subsequent reads. Also in this case,
98 the connection should be finally closed with socket:close().
101 ### socket:flush(...)
103 Same as socket:write(...) but additionally flushes the socket (i.e. all pending
104 data is passed to the operating system).
106 In case of an I/O error, nil (as first return value) plus an error message (as
107 second return value) are returned. On success, the socket userdata object is
108 returned.
111 ### socket:flush_nb(...)
113 Same as socket:write_nb(...) but additionally flushes the socket (i.e. all
114 pending data is passed to the operating system). The total number of bytes that
115 could not be passed yet to the operating system is returned. Zero is returned
116 if all data could be flushed out.
118 In case of an I/O error, nil (as first return value) plus an error message (as
119 second return value) are returned.
122 ### socket.interval
124 Set to the name of an interval timer if the "connect" handler was called due to
125 an elapsed interval timer. Otherwise nil.
128 ### socket.local_ip4
130 Local IPv4 address used for the connection. Encoded as 4 raw bytes in form of a
131 string.
134 ### socket.local_ip6
136 Local IPv6 address used for the connection. Encoded as 16 raw bytes in form of
137 a string.
140 ### socket.local_tcpport
142 Local TCP port used for the connection.
145 ### socket:read(maxlen, terminator)
147 Reads up to maxlen bytes or until an optional termination character is
148 encountered (which is included in the result). The maxlen value may be nil, in
149 which case there is no limit on the number of bytes read.
151 In case of an I/O error, nil (as first return value) plus an error message (as
152 second return value) are returned.
154 In all other cases (including EOF), the following two values are returned:
156 - a string containing the bytes read (first return value, may be empty string)
157 - a status code equal to "term", "maxlen", or "eof" (second return value)
159 If an EOF is encountered before all data could be read, then "eof" is returned
160 as second return value. If maxlen bytes have been read and no termination
161 character has been read, then "maxlen" is returned as second return value. If
162 the termination character is the last character of the read string, the second
163 return value will be "term".
166 ### socket:read_call(waitfunc, maxlen, terminator)
168 Same as socket:read(maxlen, terminator), but calls waitfunc(socket, "r") (in an
169 infinite loop) as long as the reading is blocked.
172 ### socket:read_nb(maxlen, terminator)
174 Same as socket:read(maxlen, terminator), but does not block.
176 In case of an I/O error, nil (as first return value) plus an error message (as
177 second return value) are returned.
179 In all other cases (including EOF), the following two values are returned:
181 - a string containing the bytes read (first return value, may be empty string)
182 - a status code equal to "term", "maxlen", "eof", "block" (second return value)
184 The status code "block" as second return value is used if the function returned
185 prematurely because it would block otherwise. In this case, the first return
186 value is a string that contains the bytes that could be read without blocking.
189 ### socket:read_yield(maxlen, terminator)
191 Alias for socket:read_call(coroutine.yield, maxlen, terminator)
194 ### socket.remote_ip4
196 Remote IPv4 address used for the connection. Encoded as 4 raw bytes in form of
197 a string.
200 ### socket.remote_ip6
202 Remote IPv6 address used for the connection. Encoded as 16 raw bytes in form of
203 a string.
206 ### socket.remote_tcpport
208 Remote TCP port used for the connection.
211 ### socket:reset()
213 Alias for socket:close(0). Closes the socket connection by sending a TCP RST
214 packet if possible to indicate error condition.
216 Returns true on success, or nil (as first return value) plus error message (as
217 second return value) in case of an I/O error. Using this method on sockets that
218 have already been closed (or reset) will throw an error.
220 Warning: Previously sent (and flushed) data may be lost during transmission.
223 ### socket:write(...)
225 Takes a variable number of strings and sends them to the peer. The operation is
226 buffered, so to actually send out the data, it is necessary to eventually call
227 socket:flush(), socket:finish(), or socket:close().
229 In case of an I/O error, nil (as first return value) plus an error message (as
230 second return value) are returned. On success, the socket userdata object is
231 returned.
234 ### socket:write_nb(...)
236 Takes a variable number of strings and sends them to the peer. The operation is
237 buffered, so to actually send out the data, it is necessary to eventually call
238 socket:flush_nb(), socket:flush(), socket:finish(), or socket:close().
240 This function always returns immediately (i.e. it does not block). If all data
241 (but a small buffered portion) could be sent out, then zero is returned.
242 Otherwise, all arguments that could not be sent are stored in a buffer of
243 unlimited size (up to memory capabilities) and an integer is returned that
244 indicates the number of bytes currently in the buffer.
246 In case of an I/O error, nil (as first return value) plus an error message (as
247 second return value) are returned.
251 I/O library
252 -----------
254 The Moonbridge Network Server for Lua Applications comes with its own I/O
255 library to support blocking as well as nonblocking I/O operations.
257 All methods on an I/O handle (e.g. socket) are described in the previous
258 section regarding the "socket" object. All other functions of the library are
259 listed below.
262 ### moonbridge_io.localconnect(path)
264 Tries to connect to a local socket (also known as Unix Domain Socket). Returns
265 a socket object on success, or nil (as first return value) plus an error
266 message (as second return value) in case of error.
269 ### moonbridge_io.localconnect_nb(path)
271 Tries to connect to a local socket (also known as Unix Domain Socket). Returns
272 a socket object on success, or nil (as first return value) plus an error
273 message (as second return value) in case of error.
275 Same as moonbridge_io.localconnect(path), except that this function does not
276 block and immediately returns a socket object.
278 In case of an I/O error, nil (as first return value) plus an error message (as
279 second return value) may be returned. However, connection errors may also be
280 reported on first read or write on the socket.
283 ### moonbridge_io.locallisten(path)
285 Attempts to create a local socket (also known as Unix Domain Socket) to accept
286 incoming connections. If the file does already exist and is a socket, then it
287 is deleted automatically before being re-created.
289 In case of an I/O error, nil (as first return value) plus an error message (as
290 second return value) may be returned.On success, a listener object is returned
291 which supports the methods :accept(), :accept_nb(), and :close().
293 The method :accept() blocks until a new incoming connection is available in
294 which case a socket object is returned.
296 The method :accept_nb() works like :accept(), except that the call is
297 nonblocking and returns false (plus a notice as second return value) in case no
298 incoming connection is available. It is possible to wait for an incoming
299 connection by including the listener object in the input_set of the
300 moonbridge_io.poll(...) call.
302 The method :close() will close the listening socket. In case of local sockets
303 (Unix Domain Sockets), the socket will not be unlinked in the file system.
305 I/O errors by the methods of the listener object are also reported by returning
306 nil (as first return value) plus an error message (as second return value).
309 ### moonbridge_io.poll(input_set, output_set, timeout)
311 This function waits for at least one of the given file descriptors and/or
312 I/O handles to be ready for input or output. The two sets of file descriptors
313 and/or handles must contain the file descriptor or handle as a key, and a value
314 which does evaluate to true. If a set is nil, it is treated as being empty.
316 Returns true when at least one file descriptor or handle is ready for reading
317 or writing respectively. Returns false (as first return value) plus a status
318 message (as second return value) in case of timeout or when a signal was
319 received.
322 ### moonbridge_io.tcpconnect(hostname, port)
324 Tries to open a TCP connection with the given host and TCP port number. Returns
325 a socket object on success, or nil (as first return value) plus an error
326 message (as second return value) in case of error.
329 ### moonbridge_io.tcpconnect_nb(hostname, port)
331 Same as moonbridge_io.tcpconnect(hostname, port), except that this function
332 does not block and immediately returns a socket object.
334 Note: The current implementation still blocks during the DNS lookup. Use a
335 numeric IP address as hostname to be truly nonblocking.
337 In case of an I/O error, nil (as first return value) plus an error message (as
338 second return value) may be returned. However, connection errors may also be
339 reported on first read or write on the socket.
342 ### moonbridge_io.tcplisten(hostname, port)
344 Attempts to open a TCP port for listening. To listen on the loopback interface,
345 use "::1" as hostname if IPv6 shall be used, or use "127.0.0.1" as hostname if
346 IPv4 shall be used. To listen on all available interfaces, use "::" (IPv6) or
347 "0.0.0.0" (IPv4) respectively.
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. On success, a listener object is returned
351 which supports the methods :accept(), :accept_nb(), and :close(). See reference
352 for moonbridge.io_locallisten(...).
356 HTTP module
357 -----------
359 The http module exports the function http.generate_handler(callback) that
360 converts an HTTP handler to a "connect" handler. See file "example.lua" for an
361 example of invocation. A table with options may be passed either as a second
362 argument, or as a first argument preceeding the callback function (whichever is
363 more convenient).
365 The following options are supported:
367 - request_body_size_limit: maximum size of payload of HTTP request body
368 (transfer encoding is allowed to add a limited amount of extra data)
369 - chunk_size: optional default value for maximum_input_chunk_size and
370 minimum_output_chunk_size
371 - request_header_size_limit: maximum size of HTTP request headers
372 - maximum_input_chunk_size: maximum chunk size when streaming a request body or
373 certain POST fields (bigger chunks will be fragmented automatically)
374 - minimum_output_chunk_size: minimum size for a chunk when sending a response
375 body (smaller chunks will be buffered and concatenated with future data;
376 ignored when request:flush() is called)
377 - static_headers: a set of headers to be included in every HTTP response
378 (may be a string, a table or strings, or a table of key-value pairs)
380 The callback function receives a single request object as argument, which is
381 described below.
384 ### request.body
386 The request body (without headers) as a string. Accessing this value makes
387 further access to request.post_params and request.post_params_list, or
388 invocation of request:stream_request_body(...) impossible.
391 ### request:close_after_finish()
393 Closes the connection after answering the request.
395 This method can only be called before the HTTP response header section has been
396 finished (i.e. before request:finish_headers(), request:send_data(...), or
397 request:finish() were called), but it may be called before a status code has
398 been sent using request:send_status(...).
400 A corresponding "Connection: close" header is automatically sent.
403 ### request.cookies
405 A table with all cookies sent by the client.
408 ### request.defer_reading()
410 Disables automatic request body processing on write. Can be called before
411 sending a HTTP status code to send a response before the request has been fully
412 received.
414 CAUTION: Responding to a request before the request body has been processed may
415 lead to a deadlock if the browser does not process the response while trying to
416 send the request. Therefore, this function should only be used if:
418 - the TCP stack has enough buffer space for the response (i.e. if the response
419 is small enough), and if
420 - a timer is used to cancel the response in case of a deadlock.
422 It is recommended to not use this function unless certain performance tweaks
423 are desired.
426 ### request.faulty
428 Normally set to false. In case of a read or write error on the client
429 connection, this value is set to true before a Lua error is raised.
431 A faulty request handle must not be used, or another Lua error will be raised.
434 ### request:finish()
436 Finishes and flushes a HTTP response. May be called multiple times. An
437 HTTP status, all headers, and the response body (if applicable) must have been
438 previously sent. After calling this method, no further data may be written.
441 ### request:finish_headers()
443 Finishes and flushes the HTTP response header section. May be called multiple
444 times, as long as the request is not finished completely. This method is
445 automatically invoked if the application is beginning to send a response body.
446 After calling this method, no further headers may be sent.
449 ### request:flush()
451 Flushes any pending output data. Note: In order to mark the end of a response
452 body, it is required to call request:finish().
455 ### request.get_params
457 A table that maps field names to their corresponding GET value. If there are
458 several GET values with the given field name, then the first value is used.
460 Note: May be implemented through metamethods, but does support iteration
461 through pairs(...).
464 ### request.get_params_list
466 A table that maps field names to a sequence of their corresponding GET values.
468 Note: May be implemented through metamethods, but does support iteration
469 through pairs(...).
472 ### request.headers
474 A table that maps (case-insensitively) a HTTP header field name to a sequence
475 of values. One entry is created for every occurrence of a header line with the
476 given field name).
479 ### request.headers_csv_string
481 A table that maps (case-insensitively) a HTTP header field name to a comma
482 separated string. Multiple occurrences of the header with the given field name
483 are automatically merged into the comma separated string.
486 ### request.headers_csv_table
488 A table that maps (case-insensitively) a HTTP header field name to a sequence
489 of values. One entry is created for every comma separated value of each header
490 with the given field name.
493 ### request.headers_flags
495 A table that maps (case-insensitively) a HTTP header field name to another
496 table which (again case-insensitively) maps a string to a boolean, depending on
497 whether this string occurred in the list of comma separated values of one
498 header line with the given field name that was the key in the first table.
501 ### request.headers_value
503 A table that maps (case-insensitively) a HTTP header field name to a value. If
504 multiple header lines with the given field name have been received, false is
505 used as value.
508 ### request.method
510 The HTTP request method, e.g. "HEAD", "GET", or "POST".
513 ### request.path
515 The requested path without a leading slash and without the query part (e.g.
516 "index.html" if "/index.html?a=b&c=d" has been requested). For the query part,
517 see request.query.
519 This value will be nil if (and only if) the request method is "OPTIONS" with a
520 request target equal to "*" (see also asterisk-form of request-target in
521 section 5.3.4 in RFC 7230).
524 ### request.post_metadata
526 Only set for multipart/form-data POST requests. A table that maps field names
527 to their corresponding POST metadata table which contains two entries:
528 "file_name" and "content_type". If there are several POST values with the given
529 field name, then the first value/file is used.
532 ### request.post_metadata_list
534 Only set for multipart/form-data POST requests. A table that maps field names
535 to a sequence with their corresponding POST metadata tables. Needed if multiple
536 files are uploaded with the same field name.
539 ### request.post_params
541 A table that maps field names to their corresponding POST value. If there are
542 several POST values with the given field name, then the first value is used.
544 Note: May be implemented through metamethods, but does support iteration
545 through pairs(...).
548 ### request.post_params_list
550 A table that maps field names to a sequence of their corresponding POST values.
552 Note: May be implemented through metamethods, but does support iteration
553 through pairs(...).
556 ### request.query
558 Query part of the request target including the leading question mark, e.g.
559 "?a=b&c=d" if the requested target is "/index.html?a=b&c=d". The data is
560 automatically parsed and made available through request.get_params and
561 request.get_params_list.
563 If there is no query part given in the request target, then this string is
564 the empty string. This value will be nil if (and only if) the request method
565 is "OPTIONS" with a request target equal to "*" (see also asterisk-form of
566 request-target in section 5.3.4 in RFC 7230).
569 ### request:process_request_body()
571 Starts processing the request body (if existent) to set the values
572 request.post_params, request.post_params_list, request.post_metadata, and
573 and request.post_metadata_list and/or to call POST field stream handlers that
574 have been previously registered with request:stream_post_param(...) or
575 request:stream_post_params(...).
577 This method gets invoked automatically when the POST param tables
578 (request.post_params, etc.) are accessed, or if a response is sent (to avoid
579 deadlocks with the webbrowser). (Note: Automatic request body processing on
580 write may be disabled by calling request:defer_reading().)
582 After this method returned, all registered POST field stream handlers have
583 received all data. Registration of other POST field stream handlers is not
584 possible after this method has been called (or after request.post_params_list
585 or request.post_params have been accessed).
588 ### request:send_data(...)
590 Sends data as response body. All arguments are converted via tostring(...) and
591 concatenated. May be called multiple times until the request has been finished
592 by calling request:finish().
594 If the request method (see request.method) is "HEAD", then calls to
595 request:send_data(...) are automatically ignored.
598 ### request:send_header(key, value)
600 Sends a HTTP response header that consists of the given key and the given
601 value. Note: Key and value must be provided as separate arguments. Before any
602 headers can be sent, a HTTP status must have been set with
603 request:send_status(status_string).
606 ### request:send_status(status_string)
608 Sends a HTTP response status that is given as a string consisting of a 3-digit
609 number and an explanatory string, e.g. "200 OK" or "404 Not Found". This
610 function must be called once before any headers or response body data may be
611 sent.
614 ### request.socket
616 The underlaying socket. Can be used to force a TCP RST, etc.
619 ### request:stream_post_param(field_name, callback)
621 Registers a stream handler for the given POST parameter. The callback function
622 will be called in the following manner:
624 - For the initial chunk, the first chunk gets passed as first argument while a
625 table with metadata ("field_name" and "content_type") gets passed as second
626 argument. In case of an immediate EOF (i.e. an empty file), the passed
627 chunk is the empty string. In all other cases the chunk has a length greater
628 than zero.
629 - For any remaining chunks, the respective chunk gets passed as first and only
630 argument (no metadata). Here, the chunk has always a length greater than
631 zero.
632 - To indicate the end of the stream, the callback function is called without
633 arguments. This also happens in case of an immediate EOF (see above).
635 In case of an immediate EOF (i.e. an empty file), the callback function is thus
636 called as follows:
638 - The first time with an empty string as first argument, and with the metadata
639 as second argument.
640 - The second time without any arguments.
643 ### request:stream_post_params(pattern, callback)
645 Same as request:stream_post_param(...) but providing a string pattern to match
646 multiple field names (e.g. "^file_[0-9]+$").
649 ### request:stream_request_body(callback)
651 Start streaming of request body. For each chunk of the request body, the
652 callback function is called with the corresponding chunk. End of data is
653 indicated through return of request:stream_request_body(...) (not by calling
654 the callback without arguments).
656 The function may be called with nil instead of a callback function. In this
657 case, the request body is read and discarded. Only if nil is passed instead of
658 a callback, then the function may also be invoked when the request body has
659 already been read and/or processed. In the latter case, the function performs
660 no operation.