moonbridge
view reference.txt @ 105:11d03470ef19
Refined buffer model for reading in I/O library
| author | jbe |
|---|---|
| date | Wed Apr 08 19:37:09 2015 +0200 (2015-04-08) |
| parents | 51ff6ad11677 |
| children | 8fce76ef321f |
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. If no bytes could be read but EOF was encountered,
74 then true is returned.
76 In case of an I/O error, nil (as first return value) plus an error message (as
77 second result value) are returned.
80 ### socket:drain_nb(maxlen, terminator)
82 Same as socket:read_nb(maxlen, terminator), but discards the input and returns
83 the number of discarded bytes. If no bytes could be read but EOF was
84 encountered, then true is returned.
86 In case of an I/O error, nil (as first return value) plus an error message (as
87 second result 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 result 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 result 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 Read 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 If EOF is encountered before any data could be read, then false (as first
152 return value) plus a notice string (as second return value) are returned.
154 In case of an I/O error, nil (as first return value) plus an error message (as
155 second result value) are returned.
158 ### socket:read_nb(maxlen, terminator)
160 Read up to maxlen bytes, until an optional termination character is encountered
161 (which is included in the result), or until no more data is available for
162 reading. The maxlen value may be nil, in which case there is no limit on the
163 number of bytes read.
165 If EOF is encountered before any data could be read, then false (as first
166 return value) plus a notice string (as second return value) are returned.
168 If no data was available for reading, but no EOF was encountered, then an empty
169 string is returned.
171 In case of an I/O error, nil (as first return value) plus an error message (as
172 second result value) are returned.
175 ### socket.remote_ip4
177 Remote IPv4 address used for the connection. Encoded as 4 raw bytes in form of
178 a string.
181 ### socket.remote_ip6
183 Remote IPv6 address used for the connection. Encoded as 16 raw bytes in form of
184 a string.
187 ### socket.remote_tcpport
189 Remote TCP port used for the connection.
192 ### socket:reset()
194 Alias for socket:close(0). Closes the socket connection by sending a TCP RST
195 packet if possible to indicate error condition.
197 Returns true on success, or nil (as first result value) plus error message (as
198 second result value) in case of an I/O error. Using this method on sockets that
199 have already been closed (or reset) will throw an error.
201 Warning: Previously sent (and flushed) data may be lost during transmission.
204 ### socket:write(...)
206 Takes a variable number of strings and sends them to the peer. The operation is
207 buffered, so to actually send out the data, it is necessary to eventually call
208 socket:flush(), socket:finish(), or socket:close().
210 In case of an I/O error, nil (as first return value) plus an error message (as
211 second result value) are returned. On success, the socket userdata object is
212 returned.
215 ### socket:write_nb(...)
217 Takes a variable number of strings and sends them to the peer. The operation is
218 buffered, so to actually send out the data, it is necessary to eventually call
219 socket:flush_nb(), socket:flush(), socket:finish(), or socket:close().
221 This function always returns immediately (i.e. it does not block). If all data
222 (but a small buffered portion) could be sent out, then zero is returned.
223 Otherwise, all arguments that could not be sent are stored in a buffer of
224 unlimited size (up to memory capabilities) and an integer is returned that
225 indicates the number of bytes currently in the buffer.
227 In case of an I/O error, nil (as first return value) plus an error message (as
228 second result value) are returned.
232 I/O library
233 -----------
235 The Moonbridge Network Server for Lua Applications comes with its own I/O
236 library to support blocking as well as nonblocking I/O operations.
239 ### moonbridge_io.tcpconnect(hostname, port)
241 Tries to open a TCP connection with the given host and TCP port number. Returns
242 a socket object on success (methods see above), or nil (as first return value)
243 plus an error message (as second return value) in case of error.
246 ### moonbridge_io.tcpconnect_nb(hostname, port)
248 Same as moonbridge_io.tcpconnect(hostname, port), except that this function
249 does not block and immediately returns a socket object.
251 Note: The current implementation still blocks during the DNS lookup. Use a
252 numeric IP address as hostname to be truly nonblocking.
254 In case of an I/O error, nil (as first return value) plus an error message (as
255 second result value) may be returned. However, connection errors may also be
256 reported on first read or write on the socket.
260 HTTP module
261 -----------
263 The http module exports the function http.generate_handler(callback) that
264 converts an HTTP handler to a "connect" handler. See file "example.lua" for an
265 example of invocation. A table with options may be passed either as a second
266 argument, or as a first argument preceeding the callback function (whichever is
267 more convenient).
269 The following options are supported:
271 - request_body_size_limit: maximum size of payload of HTTP request body
272 (transfer encoding is allowed to add a limited amount of extra data)
273 - chunk_size: optional default value for maximum_input_chunk_size and
274 minimum_output_chunk_size
275 - request_header_size_limit: maximum size of HTTP request headers
276 - maximum_input_chunk_size: maximum chunk size when streaming a request body or
277 certain POST fields (bigger chunks will be fragmented automatically)
278 - minimum_output_chunk_size: minimum size for a chunk when sending a response
279 body (smaller chunks will be buffered and concatenated with future data;
280 ignored when request:flush() is called)
281 - static_headers: a set of headers to be included in every HTTP response
282 (may be a string, a table or strings, or a table of key-value pairs)
284 The callback function receives a single request object as argument, which is
285 described below.
288 ### request.body
290 The request body (without headers) as a string. Accessing this value makes
291 further access to request.post_params and request.post_params_list, or
292 invocation of request:stream_request_body(...) impossible.
295 ### request:close_after_finish()
297 Closes the connection after answering the request.
299 This method can only be called before the HTTP response header section has been
300 finished (i.e. before request:finish_headers(), request:send_data(...), or
301 request:finish() were called), but it may be called before a status code has
302 been sent using request:send_status(...).
304 A corresponding "Connection: close" header is automatically sent.
307 ### request.cookies
309 A table with all cookies sent by the client.
312 ### request.defer_reading()
314 Disables automatic request body processing on write. Can be called before
315 sending a HTTP status code to send a response before the request has been fully
316 received.
318 CAUTION: Responding to a request before the request body has been processed may
319 lead to a deadlock if the browser does not process the response while trying to
320 send the request. Therefore, this function should only be used if:
322 - the TCP stack has enough buffer space for the response (i.e. if the response
323 is small enough), and if
324 - a timer is used to cancel the response in case of a deadlock.
326 It is recommended to not use this function unless certain performance tweaks
327 are desired.
330 ### request.faulty
332 Normally set to false. In case of a read or write error on the client
333 connection, this value is set to true before a Lua error is raised.
335 A faulty request handle must not be used, or another Lua error will be raised.
338 ### request:finish()
340 Finishes and flushes a HTTP response. May be called multiple times. An
341 HTTP status, all headers, and the response body (if applicable) must have been
342 previously sent. After calling this method, no further data may be written.
345 ### request:finish_headers()
347 Finishes and flushes the HTTP response header section. May be called multiple
348 times, as long as the request is not finished completely. This method is
349 automatically invoked if the application is beginning to send a response body.
350 After calling this method, no further headers may be sent.
353 ### request:flush()
355 Flushes any pending output data. Note: In order to mark the end of a response
356 body, it is required to call request:finish().
359 ### request.get_params
361 A table that maps field names to their corresponding GET value. If there are
362 several GET values with the given field name, then the first value is used.
364 Note: May be implemented through metamethods, but does support iteration
365 through pairs(...).
368 ### request.get_params_list
370 A table that maps field names to a sequence of their corresponding GET values.
372 Note: May be implemented through metamethods, but does support iteration
373 through pairs(...).
376 ### request.headers
378 A table that maps (case-insensitively) a HTTP header field name to a sequence
379 of values. One entry is created for every occurrence of a header line with the
380 given field name).
383 ### request.headers_csv_string
385 A table that maps (case-insensitively) a HTTP header field name to a comma
386 separated string. Multiple occurrences of the header with the given field name
387 are automatically merged into the comma separated string.
390 ### request.headers_csv_table
392 A table that maps (case-insensitively) a HTTP header field name to a sequence
393 of values. One entry is created for every comma separated value of each header
394 with the given field name.
397 ### request.headers_flags
399 A table that maps (case-insensitively) a HTTP header field name to another
400 table which (again case-insensitively) maps a string to a boolean, depending on
401 whether this string occurred in the list of comma separated values of one
402 header line with the given field name that was the key in the first table.
405 ### request.headers_value
407 A table that maps (case-insensitively) a HTTP header field name to a value. If
408 multiple header lines with the given field name have been received, false is
409 used as value.
412 ### request.method
414 The HTTP request method, e.g. "HEAD", "GET", or "POST".
417 ### request.path
419 The requested path without a leading slash and without the query part (e.g.
420 "index.html" if "/index.html?a=b&c=d" has been requested). For the query part,
421 see request.query.
423 This value will be nil if (and only if) the request method is "OPTIONS" with a
424 request target equal to "*" (see also asterisk-form of request-target in
425 section 5.3.4 in RFC 7230).
428 ### request.post_metadata
430 Only set for multipart/form-data POST requests. A table that maps field names
431 to their corresponding POST metadata table which contains two entries:
432 "file_name" and "content_type". If there are several POST values with the given
433 field name, then the first value/file is used.
436 ### request.post_metadata_list
438 Only set for multipart/form-data POST requests. A table that maps field names
439 to a sequence with their corresponding POST metadata tables. Needed if multiple
440 files are uploaded with the same field name.
443 ### request.post_params
445 A table that maps field names to their corresponding POST value. If there are
446 several POST values with the given field name, then the first value is used.
448 Note: May be implemented through metamethods, but does support iteration
449 through pairs(...).
452 ### request.post_params_list
454 A table that maps field names to a sequence of their corresponding POST values.
456 Note: May be implemented through metamethods, but does support iteration
457 through pairs(...).
460 ### request.query
462 Query part of the request target including the leading question mark, e.g.
463 "?a=b&c=d" if the requested target is "/index.html?a=b&c=d". The data is
464 automatically parsed and made available through request.get_params and
465 request.get_params_list.
467 If there is no query part given in the request target, then this string is
468 the empty string. This value will be nil if (and only if) the request method
469 is "OPTIONS" with a request target equal to "*" (see also asterisk-form of
470 request-target in section 5.3.4 in RFC 7230).
473 ### request:process_request_body()
475 Starts processing the request body (if existent) to set the values
476 request.post_params, request.post_params_list, request.post_metadata, and
477 and request.post_metadata_list and/or to call POST field stream handlers that
478 have been previously registered with request:stream_post_param(...) or
479 request:stream_post_params(...).
481 This method gets invoked automatically when the POST param tables
482 (request.post_params, etc.) are accessed, or if a response is sent (to avoid
483 deadlocks with the webbrowser). (Note: Automatic request body processing on
484 write may be disabled by calling request:defer_reading().)
486 After this method returned, all registered POST field stream handlers have
487 received all data. Registration of other POST field stream handlers is not
488 possible after this method has been called (or after request.post_params_list
489 or request.post_params have been accessed).
492 ### request:send_data(...)
494 Sends data as response body. All arguments are converted via tostring(...) and
495 concatenated. May be called multiple times until the request has been finished
496 by calling request:finish().
498 If the request method (see request.method) is "HEAD", then calls to
499 request:send_data(...) are automatically ignored.
502 ### request:send_header(key, value)
504 Sends a HTTP response header that consists of the given key and the given
505 value. Note: Key and value must be provided as separate arguments. Before any
506 headers can be sent, a HTTP status must have been set with
507 request:send_status(status_string).
510 ### request:send_status(status_string)
512 Sends a HTTP response status that is given as a string consisting of a 3-digit
513 number and an explanatory string, e.g. "200 OK" or "404 Not Found". This
514 function must be called once before any headers or response body data may be
515 sent.
518 ### request.socket
520 The underlaying socket. Can be used to force a TCP RST, etc.
523 ### request:stream_post_param(field_name, callback)
525 Registers a stream handler for the given POST parameter. The callback function
526 will be called in the following manner:
528 - For the initial chunk, the first chunk gets passed as first argument while a
529 table with metadata ("field_name" and "content_type") gets passed as second
530 argument. In case of an immediate EOF (i.e. an empty file), the passed
531 chunk is the empty string. In all other cases the chunk has a length greater
532 than zero.
533 - For any remaining chunks, the respective chunk gets passed as first and only
534 argument (no metadata). Here, the chunk has always a length greater than
535 zero.
536 - To indicate the end of the stream, the callback function is called without
537 arguments. This also happens in case of an immediate EOF (see above).
539 In case of an immediate EOF (i.e. an empty file), the callback function is thus
540 called as follows:
542 - The first time with an empty string as first argument, and with the metadata
543 as second argument.
544 - The second time without any arguments.
547 ### request:stream_post_params(pattern, callback)
549 Same as request:stream_post_param(...) but providing a string pattern to match
550 multiple field names (e.g. "^file_[0-9]+$").
553 ### request:stream_request_body(callback)
555 Start streaming of request body. For each chunk of the request body, the
556 callback function is called with the corresponding chunk. End of data is
557 indicated through return of request:stream_request_body(...) (not by calling
558 the callback without arguments).
560 The function may be called with nil instead of a callback function. In this
561 case, the request body is read and discarded. Only if nil is passed instead of
562 a callback, then the function may also be invoked when the request body has
563 already been read and/or processed. In the latter case, the function performs
564 no operation.