Moonbridge reference ==================== Global function listen{...} --------------------------- This function initializes the Moonbridge Network Server. It may be called multiple times. However, it is not allowed to register additional listeners by calling listen{...} from a "prepare", "connect", or "finish" handler. See file "example.lua" for parametrization of the listen{...} function. Warning: Moonbridge will fork the Lua environment to handle parallel requests. Functions provided as "prepare", "connect", and "finish" handlers may access global variables, but for every child process these global variables will not be shared! If you require a global state, a DBMS, cache server, or similar is necessary. Global function timeout(...) ---------------------------- Calling this function with a positive number (time in seconds) sets a timer that kills the current process after the selected time runs out. The remaining time can be queried by calling this function without arguments. Calling this function with a single argument that is the number zero will disable the timeout. Another mode of operation is selected by passing two arguments: a time (in seconds) as first argument and a function as second argument. In this case, a sub-timer will be used to limit the execution time of the function. In case of timeout, the process will be killed (and the timeout function does not return). If the time for the sub-timer is longer than a previously set timeout (using the timeout(...) function with one argument), the shorter timeout (of the previous call of timeout(...)) will have precedence. Timers are also automatically reset (disabled) when a handler (prepare handler or connect handler) returns. To shutdown processes after a certain time waiting for a new request, use the idle_time parameter of the listen function. Socket object passed to "connect" handler ----------------------------------------- For every incoming connection, the registered "connect" handler is called with a single socket object as argument, which is described below: ### socket:close() Closes the socket connection (input and output stream) by flushing all data and sending a TCP FIN packet. Returns true on success, or nil plus error message in case of an I/O error. Using this method on sockets that have already been closed (or reset) will throw an error. Warning: Pending data on the input stream may cause connection aborts (TCP RST) when network connections are used. All pending input data should have been read (or drained) before calling socket:close(). Use socket:finish() to send a TCP FIN packet to the peer before waiting for EOF from the peer. A socket passed to the "connect" handler will be closed automatically if it was not closed by the "connect" handler and if the "connect" handler returns normally (i.e. without throwing an error). If the "connect" handler throws an error, then the socket will be reset. See socket:reset(). ### socket:drain(maxlen, terminator) Same as socket:read(maxlen, terminator), but discards the input and returns the number of discarded bytes (as first return value) and the status code ("term", "maxlen", "eof" as second return value). In case of an I/O error, nil (as first return value) plus an error message (as second return value) are returned. ### socket:drain_call(waitfunc, maxlen, terminator) Same as socket:drain(maxlen, terminator), but calls waitfunc(socket, "r") (in an infinite loop) as long as the reading is blocked. ### socket:drain_nb(maxlen, terminator) Same as socket:drain(maxlen, terminator), but non-blocking. The status code (which is returned as second return value) may therefore be "term", "maxlen", "eof", or "block". In case of an I/O error, nil (as first return value) plus an error message (as second return value) are returned. ### socket:drain_yield(maxlen, terminator) Alias for socket:drain_call(coroutine.yield, maxlen, terminator) ### socket:finish() Sends a TCP FIN packet to indicate EOF on write stream. Subsequent reads are still possible. When there is no more input data to be read, the connection should finally be closed with socket:close(). In case of local sockets (Unix Domain Sockets), socket:finish() simply closes the underlying socket and emulates EOF on subsequent reads. Also in this case, the connection should be finally closed with socket:close(). ### socket:flush(...) Same as socket:write(...) but additionally flushes the socket (i.e. all pending data is passed to the operating system). In case of an I/O error, nil (as first return value) plus an error message (as second return value) are returned. On success, the socket userdata object is returned. ### socket:flush_call(waitfunc, ...) Same as socket:flush(...), but calls waitfunc() (in an infinite loop) as long as the writing is blocked. ### socket:flush_nb(...) Same as socket:write_nb(...) but additionally flushes the socket (i.e. all pending data is passed to the operating system). The total number of bytes that could not be passed yet to the operating system is returned. Zero is returned if all data could be flushed out. In case of an I/O error, nil (as first return value) plus an error message (as second return value) are returned. ### socket:flush_yield(...) Alias for socket:flush_call(coroutine.yield, ...) ### socket.interval Set to the name of an interval timer if the "connect" handler was called due to an elapsed interval timer. Otherwise nil. ### socket.local_ip4 Local IPv4 address used for the connection. Encoded as 4 raw bytes in form of a string. ### socket.local_ip6 Local IPv6 address used for the connection. Encoded as 16 raw bytes in form of a string. ### socket.local_tcpport Local TCP port used for the connection. ### socket:read(maxlen, terminator) Reads up to maxlen bytes or until an optional termination character is encountered (which is included in the result). The maxlen value may be nil, in which case there is no limit on the number of bytes read. In case of an I/O error, nil (as first return value) plus an error message (as second return value) are returned. In all other cases (including EOF), the following two values are returned: - a string containing the bytes read (first return value, may be empty string) - a status code equal to "term", "maxlen", or "eof" (second return value) If an EOF is encountered before all data could be read, then "eof" is returned as second return value. If maxlen bytes have been read and no termination character has been read, then "maxlen" is returned as second return value. If the termination character is the last character of the read string, the second return value will be "term". ### socket:read_call(waitfunc, maxlen, terminator) Same as socket:read(maxlen, terminator), but calls waitfunc() (in an infinite loop) as long as the reading is blocked. ### socket:read_nb(maxlen, terminator) Same as socket:read(maxlen, terminator), but does not block. In case of an I/O error, nil (as first return value) plus an error message (as second return value) are returned. In all other cases (including EOF), the following two values are returned: - a string containing the bytes read (first return value, may be empty string) - a status code equal to "term", "maxlen", "eof", "block" (second return value) The status code "block" as second return value is used if the function returned prematurely because it would block otherwise. In this case, the first return value is a string that contains the bytes that could be read without blocking. ### socket:read_yield(maxlen, terminator) Alias for socket:read_call(coroutine.yield, maxlen, terminator) ### socket.remote_ip4 Remote IPv4 address used for the connection. Encoded as 4 raw bytes in form of a string. ### socket.remote_ip6 Remote IPv6 address used for the connection. Encoded as 16 raw bytes in form of a string. ### socket.remote_tcpport Remote TCP port used for the connection. ### socket:reset() Alias for socket:close(). Closes the socket connection by sending a TCP RST packet if possible to indicate error condition. This is the default operation when a socket handle gets garbage collected or the process is terminated abnormally. Returns true on success, or nil (as first return value) plus error message (as second return value) in case of an I/O error. Using this method on sockets that have already been closed (or reset) will throw an error. Warning: Previously sent (and flushed) data may be lost during transmission. ### socket:write(...) Takes a variable number of strings and sends them to the peer. The operation is buffered, so to actually send out the data, it is necessary to eventually call socket:flush(), socket:finish(), or socket:close(). In case of an I/O error, nil (as first return value) plus an error message (as second return value) are returned. On success, the socket userdata object is returned. ### socket:write_call(waitfunc, ...) Same as socket:write(...), but calls waitfunc() (in an infinite loop) as long as the writing is blocked. ### socket:write_nb(...) Takes a variable number of strings and sends them to the peer. The operation is buffered, so to actually send out the data, it is necessary to eventually call socket:flush_nb(), socket:flush(), socket:finish(), or socket:close(). This function always returns immediately (i.e. it does not block). If all data (but a small buffered portion) could be sent out, then zero is returned. Otherwise, all arguments that could not be sent are stored in a buffer of unlimited size (up to memory capabilities) and an integer is returned that indicates the number of bytes currently in the buffer. In case of an I/O error, nil (as first return value) plus an error message (as second return value) are returned. ### socket:write_yield(...) Alias for socket:write_call(coroutine.yield, ...) I/O library ----------- The Moonbridge Network Server for Lua Applications comes with its own I/O library to support blocking as well as nonblocking I/O operations. All methods on an I/O handle (e.g. socket) are described in the previous section regarding the "socket" object. All other functions of the library are listed below. ### moonbridge_io.exec(command, arg1, arg2, ...) Executes the given command and returns a handle with three sockets named "stdin", "stdout", and "stderr" as well as the following methods: - :kill(signal) - :wait() - :wait_nb() - :wait_call(waitfunc) - :wait_yield() Use :kill(signal) to terminate the process with the given signal (defaults to 15 for SIGTERM). The :wait() method will wait for the process to terminate and return its exit code. If the process was terminated by a signal, a negative integer is returned which corresponds to the respective positive signal number. The method :wait_nb() is the same as :wait(), except that it does not block but returns false (plus a notice as second return value) if the child process has not terminated yet. The method :wait_call() is the same as :wait() but calls waitfunc() (in an infinite loop) as long as the process is still running. The method :wait_yield() is an alias for :wait_call(coroutine.yield). moonbridge_io.exec(...) returns nil (as first return value) plus an error message (as second return value) in case of error. ### moonbridge_io.localconnect(path) Tries to connect to a local socket (also known as Unix Domain Socket). Returns a socket object on success, or nil (as first return value) plus an error message (as second return value) in case of error. ### moonbridge_io.localconnect_nb(path) Tries to connect to a local socket (also known as Unix Domain Socket). Returns a socket object on success, or nil (as first return value) plus an error message (as second return value) in case of error. Same as moonbridge_io.localconnect(path), except that this function does not block and immediately returns a socket object. In case of an I/O error, nil (as first return value) plus an error message (as second return value) may be returned. However, connection errors may also be reported on first read or write on the socket. ### moonbridge_io.locallisten(path) Attempts to create a local socket (also known as Unix Domain Socket) to accept incoming connections. If the file does already exist and is a socket, then it is deleted automatically before being re-created. In case of an I/O error, nil (as first return value) plus an error message (as second return value) may be returned. On success, a listener object is returned which supports the methods :accept(), :accept_nb(), and :close(). The method :accept() blocks until a new incoming connection is available, in which case a socket object is returned. The method :accept_nb() works like :accept(), except that the call is nonblocking and returns false (plus a notice as second return value) in case no incoming connection is available. It is possible to wait for an incoming connection by including the listener object in the input_set of the moonbridge_io.poll(...) call. The method :close() will close the listening socket. In case of local sockets (Unix Domain Sockets), the socket will not be unlinked in the file system. I/O errors by the methods of the listener object are also reported by returning nil (as first return value) plus an error message (as second return value). ### moonbridge_io.poll(input_set, output_set, timeout) This function waits for at least one of the given file descriptors and/or I/O handles to be ready for input or output. The two sets of file descriptors and/or handles must contain the file descriptor or handle as a key, and a value which does evaluate to true, e.g. input_set = {[socketA] = true}. If a set is nil, it is treated as being empty. Returns true when at least one file descriptor or handle is ready for reading or writing respectively. Returns false (plus a notice as second return value) in case of timeout. Returns nil (plus a notice as second return value) if a signal was received during waiting. ### moonbridge_io.tcpconnect(hostname, port) Tries to open a TCP connection with the given host and TCP port number. Returns a socket object on success, or nil (as first return value) plus an error message (as second return value) in case of error. ### moonbridge_io.tcpconnect_nb(hostname, port) Same as moonbridge_io.tcpconnect(hostname, port), except that this function does not block and immediately returns a socket object. Note: The current implementation still blocks during the DNS lookup. Use a numeric IP address as hostname to be truly nonblocking. In case of an I/O error, nil (as first return value) plus an error message (as second return value) may be returned. However, connection errors may also be reported on first read or write on the socket. ### moonbridge_io.tcplisten(hostname, port) Attempts to open a TCP port for listening. To listen on the loopback interface, use "::1" as hostname if IPv6 shall be used, or use "127.0.0.1" as hostname if IPv4 shall be used. To listen on all available interfaces, use "::" (IPv6) or "0.0.0.0" (IPv4) respectively. In case of an I/O error, nil (as first return value) plus an error message (as second return value) may be returned. On success, a listener object is returned which supports the methods :accept(), :accept_nb(), and :close(). See reference for moonbridge.io_locallisten(...). ### moonbridge_io.timeref(previous) Helper function which returns a time reference (in SI-seconds). If a value is passed as an optional argument to the function, then that value is substracted from the result. A common idiom is: local starttime = moonbridge_io.timeref() [...] while true do [...] if not moonbridge_io.poll( input_set, output_set, timeout - moonbridge_io.timeref(starttime) ) then error("Timeout or signal received!") end [...] end HTTP module ----------- The HTTP module exports the function moonbridge_http.generate_handler(callback) that converts an HTTP handler to a "connect" handler. See file "helloworld.lua" for a simple example or "example_application.lua" for a more complex example of invocation. A table with options may be passed either as a second argument, or as a first argument preceeding the callback function (whichever is more convenient). The following options are supported: - request_body_size_limit: maximum size of payload of HTTP request body (transfer encoding is allowed to add a limited amount of extra data) - chunk_size: optional default value for maximum_input_chunk_size and minimum_output_chunk_size - request_header_size_limit: maximum size of HTTP request headers - maximum_input_chunk_size: maximum chunk size when streaming a request body or certain POST fields (bigger chunks will be fragmented automatically) - minimum_output_chunk_size: minimum size for a chunk when sending a response body (smaller chunks will be buffered and concatenated with future data; ignored when request:flush() is called) - static_headers: a set of headers to be included in every HTTP response (may be a string, a table or strings, or a table of key-value pairs) The callback function receives a single request object as argument, which is described below. ### request.body The request body (without headers) as a string. Accessing this value makes further access to request.post_params and request.post_params_list, or invocation of request:stream_request_body(...) impossible. ### request:close_after_finish() Closes the connection after answering the request. This method can only be called before the HTTP response header section has been finished (i.e. before request:finish_headers(), request:send_data(...), or request:finish() were called), but it may be called before a status code has been sent using request:send_status(...). A corresponding "Connection: close" header is automatically sent. See also request:monologue(). ### request:consume_input() Starts processing the request body (if existent) to set the values request.post_params, request.post_params_list, request.post_metadata, and and request.post_metadata_list and/or to call POST field stream handlers that have been previously registered with request:stream_post_param(...) or request:stream_post_params(...), or to call a previously registered request body stream handler that was set with request:set_request_body_streamer(). This method gets invoked automatically when the POST param tables (request.post_params, etc.) are accessed or if request.body is accessed. ### request.cookies A table with all cookies sent by the client. ### request.faulty Normally set to false. In case of a write error on the client connection or certain other unexpected errors, this value is set to true before a Lua error is raised. A faulty request handle must not be used, or another Lua error will be raised. ### request:finish() Finishes and flushes a HTTP response. An HTTP status, all headers, and the response body (if applicable) must have been previously sent. May be called multiple times (performs no operation if called on a finished request handle). Gets automatically invoked when the callback handler returns. After calling this method explicitly, no further data may be written. ### request:finish_headers() Finishes and flushes the HTTP response header section. May be called multiple times, as long as the request is not finished completely. This method is automatically invoked if the application is beginning to send a response body. After calling this method, no further headers may be sent. ### request:flush() Flushes any pending output data. Note: In order to mark the end of a response body, it is required to call request:finish(). ### request.fresh Set to false whenever the request object has been used (e.g. data has been read or sent out, or a stream handler was installed); true otherwise. ### request.get_params A table that maps field names to their corresponding GET value. If there are several GET values with the given field name, then the first value is used. Note: May be implemented through metamethods, but does support iteration through pairs(...). ### request.get_params_list A table that maps field names to a sequence of their corresponding GET values. Note: May be implemented through metamethods, but does support iteration through pairs(...). ### request.headers A table that maps (case-insensitively) a HTTP header field name to a sequence of values. For each occurrence of the respective header line, a string entry is created in that sequence. Non-existent headers are mapped to an empty table. ### request.headers_csv_string A table that maps (case-insensitively) a HTTP header field name to a comma separated string. Multiple occurrences of the header with the given field name are automatically merged into the comma separated string. ### request.headers_csv_table A table that maps (case-insensitively) a HTTP header field name to a sequence of values. One entry is created in that sequence for every comma separated value of each header with the given field name. ### request.headers_flags A table that maps (case-insensitively) a HTTP header field name to another table which (again case-insensitively) maps a string to a boolean, depending on whether this string occurred in the list of comma separated values of one header line with the given field name that was the key in the first table. ### request.headers_value A table that maps (case-insensitively) a HTTP header field name to a value. If multiple header lines with the given field name have been received, false is used as value. ### request.method The HTTP request method, e.g. "HEAD", "GET", or "POST". ### request:monologue() Same as request:close_after_finish() but additionally discards all input data immediately. ### request.path The requested path without a leading slash and without the query part (e.g. "index.html" if "/index.html?a=b&c=d" has been requested). For the query part, see request.query. This value will be nil if (and only if) the request method is "OPTIONS" with a request target equal to "*" (see also asterisk-form of request-target in section 5.3.4 in RFC 7230). ### request.post_metadata Only set for multipart/form-data POST requests. A table that maps field names to their corresponding POST metadata table which contains two entries: "file_name" and "content_type". If there are several POST values with the given field name, then the first value/file is used. Note: May be implemented through metamethods, but does support iteration through pairs(...). ### request.post_metadata_list Only set for multipart/form-data POST requests. A table that maps field names to a sequence with their corresponding POST metadata tables. Needed if multiple files are uploaded with the same field name. Note: May be implemented through metamethods, but does support iteration through pairs(...). ### request.post_params A table that maps field names to their corresponding POST value. If there are several POST values with the given field name, then the first value is used. Note: May be implemented through metamethods, but does support iteration through pairs(...). ### request.post_params_list A table that maps field names to a sequence of their corresponding POST values. Note: May be implemented through metamethods, but does support iteration through pairs(...). ### request.query Query part of the request target including the leading question mark, e.g. "?a=b&c=d" if the requested target is "/index.html?a=b&c=d". The data is automatically parsed and made available through request.get_params and request.get_params_list. If there is no query part given in the request target, then this string is the empty string. This value will be nil if (and only if) the request method is "OPTIONS" with a request target equal to "*" (see also asterisk-form of request-target in section 5.3.4 in RFC 7230). ### request:send_data(...) Sends data as response body. All arguments are converted via tostring(...) and concatenated. May be called multiple times until the request has been finished by calling request:finish(). If the request method (see request.method) is "HEAD", then calls to request:send_data(...) are automatically ignored. ### request:send_header(key, value) Sends a HTTP response header that consists of the given key and the given value. Note: Key and value must be provided as separate arguments. Before any headers can be sent, a HTTP status must have been set with request:send_status(status_string). ### request:send_status(status_string) Sends a HTTP response status that is given as a string consisting of a 3-digit number and an explanatory string, e.g. "200 OK" or "404 Not Found". This function must be called once before any headers or response body data may be sent. ### request.socket The underlaying socket. Can be used to force a TCP RST, etc. ### request:stream_post_param(field_name, callback) Registers a stream handler for the given POST parameter. The callback function will be called in the following manner: - For the initial chunk, the first chunk gets passed as first argument while a table with metadata ("field_name" and "content_type") gets passed as second argument. In case of an immediate EOF (i.e. an empty file), the passed chunk is the empty string. In all other cases the chunk has a length greater than zero. - For any remaining chunks, the respective chunk gets passed as first and only argument (no metadata). Here, the chunk has always a length greater than zero. - To indicate the end of the stream, the callback function is called without arguments. This also happens in case of an immediate EOF (see above). In case of an immediate EOF (i.e. an empty file), the callback function is thus called as follows: - The first time with an empty string as first argument, and with the metadata as second argument. - The second time without any arguments. Note that request:consume_input() needs to be called to enforce streaming to finish. ### request:stream_post_params(pattern, callback) Same as request:stream_post_param(...) but providing a string pattern to match multiple field names (e.g. "^file_[0-9]+$"). ### request:stream_request_body(callback) Registeres a stream handler for the whole request body. For each chunk of the request body, the callback function is called with the corresponding chunk. End of data is indicated by passing a nil value to the callback functuion. Note that request:consume_input() needs to be called to enforce streaming to finish. ### request:stream_request_body_now(callback) Start streaming of request body immediately. On EOF the function returns and the callback function is *not* called with nil as argument.