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#!/usr/bin/python # # Urwid web (CGI/Asynchronous Javascript) display module # Copyright (C) 2004-2007 Ian Ward # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA # # Urwid web site: http://excess.org/urwid/ from __future__ import division, print_function """ Urwid web application display module """ import os import sys import signal import random import select import socket import glob from urwid import util _js_code = r""" // Urwid web (CGI/Asynchronous Javascript) display module // Copyright (C) 2004-2005 Ian Ward // // This library is free software; you can redistribute it and/or // modify it under the terms of the GNU Lesser General Public // License as published by the Free Software Foundation; either // version 2.1 of the License, or (at your option) any later version. // // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU // Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public // License along with this library; if not, write to the Free Software // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA // // Urwid web site: http://excess.org/urwid/ colours = new Object(); colours = { '0': "black", '1': "#c00000", '2': "green", '3': "#804000", '4': "#0000c0", '5': "#c000c0", '6': "teal", '7': "silver", '8': "gray", '9': "#ff6060", 'A': "lime", 'B': "yellow", 'C': "#8080ff", 'D': "#ff40ff", 'E': "aqua", 'F': "white" }; keycodes = new Object(); keycodes = { 8: "backspace", 9: "tab", 13: "enter", 27: "esc", 33: "page up", 34: "page down", 35: "end", 36: "home", 37: "left", 38: "up", 39: "right", 40: "down", 45: "insert", 46: "delete", 112: "f1", 113: "f2", 114: "f3", 115: "f4", 116: "f5", 117: "f6", 118: "f7", 119: "f8", 120: "f9", 121: "f10", 122: "f11", 123: "f12" }; var conn = null; var char_width = null; var char_height = null; var screen_x = null; var screen_y = null; var urwid_id = null; var send_conn = null; var send_queue_max = 32; var send_queue = new Array(send_queue_max); var send_queue_in = 0; var send_queue_out = 0; var check_font_delay = 1000; var send_more_delay = 100; var poll_again_delay = 500; var document_location = null; var update_method = "multipart"; var sending = false; var lastkeydown = null; function setup_connection() { if (window.XMLHttpRequest) { conn = new XMLHttpRequest(); } else if (window.ActiveXObject) { conn = new ActiveXObject("Microsoft.XMLHTTP"); } if (conn == null) { set_status("Connection Failed"); alert( "Can't figure out how to send request." ); return; } try{ conn.multipart = true; }catch(e){ update_method = "polling"; } conn.onreadystatechange = handle_recv; conn.open("POST", document_location, true); conn.setRequestHeader("X-Urwid-Method",update_method); conn.setRequestHeader("Content-type","text/plain"); conn.send("window resize " +screen_x+" "+screen_y+"\n"); } function do_poll() { if (urwid_id == null){ alert("that's unpossible!"); return; } if (window.XMLHttpRequest) { conn = new XMLHttpRequest(); } else if (window.ActiveXObject) { conn = new ActiveXObject("Microsoft.XMLHTTP"); } conn.onreadystatechange = handle_recv; conn.open("POST", document_location, true); conn.setRequestHeader("X-Urwid-Method","polling"); conn.setRequestHeader("X-Urwid-ID",urwid_id); conn.setRequestHeader("Content-type","text/plain"); conn.send("eh?"); } function handle_recv() { if( ! conn ){ return;} if( conn.readyState != 4) { return; } if( conn.status == 404 && urwid_id != null) { set_status("Connection Closed"); return; } if( conn.status == 403 && update_method == "polling" ) { set_status("Server Refused Connection"); alert("This server does not allow polling clients.\n\n" + "Please use a web browser with multipart support " + "such as Mozilla Firefox"); return; } if( conn.status == 503 ) { set_status("Connection Failed"); alert("The server has reached its maximum number of "+ "connections.\n\nPlease try again later."); return; } if( conn.status != 200) { set_status("Connection Failed"); alert("Error from server: "+conn.statusText); return; } if( urwid_id == null ){ urwid_id = conn.getResponseHeader("X-Urwid-ID"); if( send_queue_in != send_queue_out ){ // keys waiting do_send(); } if(update_method=="polling"){ set_status("Polling"); }else if(update_method=="multipart"){ set_status("Connected"); } } if( conn.responseText == "" ){ if(update_method=="polling"){ poll_again(); } return; // keepalive } if( conn.responseText == "Z" ){ set_status("Connection Closed"); update_method = null; return; } var text = document.getElementById('text'); var last_screen = Array(text.childNodes.length); for( var i=0; i<text.childNodes.length; i++ ){ last_screen[i] = text.childNodes[i]; } var frags = conn.responseText.split("\n"); var ln = document.createElement('span'); var k = 0; for( var i=0; i<frags.length; i++ ){ var f = frags[i]; if( f == "" ){ var br = document.getElementById('br').cloneNode(true); ln.appendChild( br ); if( text.childNodes.length > k ){ text.replaceChild(ln, text.childNodes[k]); }else{ text.appendChild(ln); } k = k+1; ln = document.createElement('span'); }else if( f.charAt(0) == "<" ){ line_number = parseInt(f.substr(1)); if( line_number == k ){ k = k +1; continue; } var clone = last_screen[line_number].cloneNode(true); if( text.childNodes.length > k ){ text.replaceChild(clone, text.childNodes[k]); }else{ text.appendChild(clone); } k = k+1; }else{ var span=make_span(f.substr(2),f.charAt(0),f.charAt(1)); ln.appendChild( span ); } } for( var i=k; i < text.childNodes.length; i++ ){ text.removeChild(last_screen[i]); } if(update_method=="polling"){ poll_again(); } } function poll_again(){ if(conn.status == 200){ setTimeout("do_poll();",poll_again_delay); } } function load_web_display(){ if( document.documentURI ){ document_location = document.documentURI; }else{ document_location = document.location; } document.onkeypress = body_keypress; document.onkeydown = body_keydown; document.onresize = body_resize; body_resize(); send_queue_out = send_queue_in; // don't queue the first resize set_status("Connecting"); setup_connection(); setTimeout("check_fontsize();",check_font_delay); } function set_status( status ){ var s = document.getElementById('status'); var t = document.createTextNode(status); s.replaceChild(t, s.firstChild); } function make_span(s, fg, bg){ d = document.createElement('span'); d.style.backgroundColor = colours[bg]; d.style.color = colours[fg]; d.appendChild(document.createTextNode(s)); return d; } function body_keydown(e){ if (conn == null){ return; } if (!e) var e = window.event; if (e.keyCode) code = e.keyCode; else if (e.which) code = e.which; var mod = ""; var key; if( e.ctrlKey ){ mod = "ctrl " + mod; } if( e.altKey || e.metaKey ){ mod = "meta " + mod; } if( e.shiftKey && e.charCode == 0 ){ mod = "shift " + mod; } key = keycodes[code]; if( key != undefined ){ lastkeydown = key; send_key( mod + key ); stop_key_event(e); return false; } } function body_keypress(e){ if (conn == null){ return; } if (!e) var e = window.event; if (e.keyCode) code = e.keyCode; else if (e.which) code = e.which; var mod = ""; var key; if( e.ctrlKey ){ mod = "ctrl " + mod; } if( e.altKey || e.metaKey ){ mod = "meta " + mod; } if( e.shiftKey && e.charCode == 0 ){ mod = "shift " + mod; } if( e.charCode != null && e.charCode != 0 ){ key = String.fromCharCode(e.charCode); }else if( e.charCode == null ){ key = String.fromCharCode(code); }else{ key = keycodes[code]; if( key == undefined || lastkeydown == key ){ lastkeydown = null; stop_key_event(e); return false; } } send_key( mod + key ); stop_key_event(e); return false; } function stop_key_event(e){ e.cancelBubble = true; if( e.stopPropagation ){ e.stopPropagation(); } if( e.preventDefault ){ e.preventDefault(); } } function send_key( key ){ if( (send_queue_in+1)%send_queue_max == send_queue_out ){ // buffer overrun return; } send_queue[send_queue_in] = key; send_queue_in = (send_queue_in+1)%send_queue_max; if( urwid_id != null ){ if (send_conn == undefined || send_conn.ready_state != 4 ){ send_more(); return; } do_send(); } } function do_send() { if( ! urwid_id ){ return; } if( ! update_method ){ return; } // connection closed if( send_queue_in == send_queue_out ){ return; } if( sending ){ //var queue_delta = send_queue_in - send_queue_out; //if( queue_delta < 0 ){ queue_delta += send_queue_max; } //set_status("Sending (queued "+queue_delta+")"); return; } try{ sending = true; //set_status("starting send"); if( send_conn == null ){ if (window.XMLHttpRequest) { send_conn = new XMLHttpRequest(); } else if (window.ActiveXObject) { send_conn = new ActiveXObject("Microsoft.XMLHTTP"); } }else if( send_conn.status != 200) { alert("Error from server: "+send_conn.statusText); return; }else if(send_conn.readyState != 4 ){ alert("not ready on send connection"); return; } } catch(e) { alert(e); sending = false; return; } send_conn.open("POST", document_location, true); send_conn.onreadystatechange = send_handle_recv; send_conn.setRequestHeader("Content-type","text/plain"); send_conn.setRequestHeader("X-Urwid-ID",urwid_id); var tmp_send_queue_in = send_queue_in; var out = null; if( send_queue_out > tmp_send_queue_in ){ out = send_queue.slice(send_queue_out).join("\n") if( tmp_send_queue_in > 0 ){ out += "\n" + send_queue.slice(0,tmp_send_queue_in).join("\n"); } }else{ out = send_queue.slice(send_queue_out, tmp_send_queue_in).join("\n"); } send_queue_out = tmp_send_queue_in; //set_status("Sending"); send_conn.send( out +"\n" ); } function send_handle_recv() { if( send_conn.readyState != 4) { return; } if( send_conn.status == 404) { set_status("Connection Closed"); update_method = null; return; } if( send_conn.status != 200) { alert("Error from server: "+send_conn.statusText); return; } sending = false; if( send_queue_out != send_queue_in ){ send_more(); } } function send_more(){ setTimeout("do_send();",send_more_delay); } function check_fontsize(){ body_resize() setTimeout("check_fontsize();",check_font_delay); } function body_resize(){ var t = document.getElementById('testchar'); var t2 = document.getElementById('testchar2'); var text = document.getElementById('text'); var window_width; var window_height; if (window.innerHeight) { window_width = window.innerWidth; window_height = window.innerHeight; }else{ window_width = document.documentElement.clientWidth; window_height = document.documentElement.clientHeight; //var z = "CI:"; for(var i in bod){z = z + " " + i;} alert(z); } char_width = t.offsetLeft / 44; var avail_width = window_width-18; var avail_width_mod = avail_width % char_width; var x_size = (avail_width - avail_width_mod)/char_width; char_height = t2.offsetTop - t.offsetTop; var avail_height = window_height-text.offsetTop-10; var avail_height_mod = avail_height % char_height; var y_size = (avail_height - avail_height_mod)/char_height; text.style.width = x_size*char_width+"px"; text.style.height = y_size*char_height+"px"; if( screen_x != x_size || screen_y != y_size ){ send_key("window resize "+x_size+" "+y_size); } screen_x = x_size; screen_y = y_size; } """ ALARM_DELAY = 60 POLL_CONNECT = 3 MAX_COLS = 200 MAX_ROWS = 100 MAX_READ = 4096 BUF_SZ = 16384 _code_colours = { 'black': "0", 'dark red': "1", 'dark green': "2", 'brown': "3", 'dark blue': "4", 'dark magenta': "5", 'dark cyan': "6", 'light gray': "7", 'dark gray': "8", 'light red': "9", 'light green': "A", 'yellow': "B", 'light blue': "C", 'light magenta': "D", 'light cyan': "E", 'white': "F", } # replace control characters with ?'s _trans_table = "?" * 32 + "".join([chr(x) for x in range(32, 256)]) _css_style = """ body { margin: 8px 8px 8px 8px; border: 0; color: black; background-color: silver; font-family: fixed; overflow: hidden; } form { margin: 0 0 8px 0; } #text { position: relative; background-color: silver; width: 100%; height: 100%; margin: 3px 0 0 0; border: 1px solid #999; } #page { position: relative; width: 100%;height: 100%;} """ # HTML Initial Page _html_page = [ """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>Urwid Web Display - ""","""</title> <style type="text/css"> """ + _css_style + """ </style> </head> <body id="body" onload="load_web_display()"> <div style="position:absolute; visibility:hidden;"> <br id="br"\> <pre>The quick brown fox jumps over the lazy dog.<span id="testchar">X</span> <span id="testchar2">Y</span></pre> </div> Urwid Web Display - <b>""","""</b> - Status: <span id="status">Set up</span> <script type="text/javascript"> //<![CDATA[ """ + _js_code +""" //]]> </script> <pre id="text"></pre> </body> </html> """] class Screen: def __init__(self): self.palette = {} self.has_color = True self._started = False started = property(lambda self: self._started) def register_palette( self, l ): """Register a list of palette entries. l -- list of (name, foreground, background) or (name, same_as_other_name) palette entries. calls self.register_palette_entry for each item in l """ for item in l: if len(item) in (3,4): self.register_palette_entry( *item ) continue assert len(item) == 2, "Invalid register_palette usage" name, like_name = item if like_name not in self.palette: raise Exception("palette entry '%s' doesn't exist"%like_name) self.palette[name] = self.palette[like_name] def register_palette_entry( self, name, foreground, background, mono=None): """Register a single palette entry. name -- new entry/attribute name foreground -- foreground colour background -- background colour mono -- monochrome terminal attribute See curses_display.register_palette_entry for more info. """ if foreground == "default": foreground = "black" if background == "default": background = "light gray" self.palette[name] = (foreground, background, mono) def set_mouse_tracking(self, enable=True): """Not yet implemented""" pass def tty_signal_keys(self, *args, **vargs): """Do nothing.""" pass def start(self): """ This function reads the initial screen size, generates a unique id and handles cleanup when fn exits. web_display.set_preferences(..) must be called before calling this function for the preferences to take effect """ global _prefs if self._started: return util.StoppingContext(self) client_init = sys.stdin.read(50) assert client_init.startswith("window resize "),client_init ignore1,ignore2,x,y = client_init.split(" ",3) x = int(x) y = int(y) self._set_screen_size( x, y ) self.last_screen = {} self.last_screen_width = 0 self.update_method = os.environ["HTTP_X_URWID_METHOD"] assert self.update_method in ("multipart","polling") if self.update_method == "polling" and not _prefs.allow_polling: sys.stdout.write("Status: 403 Forbidden\r\n\r\n") sys.exit(0) clients = glob.glob(os.path.join(_prefs.pipe_dir,"urwid*.in")) if len(clients) >= _prefs.max_clients: sys.stdout.write("Status: 503 Sever Busy\r\n\r\n") sys.exit(0) urwid_id = "%09d%09d"%(random.randrange(10**9), random.randrange(10**9)) self.pipe_name = os.path.join(_prefs.pipe_dir,"urwid"+urwid_id) os.mkfifo(self.pipe_name+".in",0o600) signal.signal(signal.SIGTERM,self._cleanup_pipe) self.input_fd = os.open(self.pipe_name+".in", os.O_NONBLOCK | os.O_RDONLY) self.input_tail = "" self.content_head = ("Content-type: " "multipart/x-mixed-replace;boundary=ZZ\r\n" "X-Urwid-ID: "+urwid_id+"\r\n" "\r\n\r\n" "--ZZ\r\n") if self.update_method=="polling": self.content_head = ( "Content-type: text/plain\r\n" "X-Urwid-ID: "+urwid_id+"\r\n" "\r\n\r\n") signal.signal(signal.SIGALRM,self._handle_alarm) signal.alarm( ALARM_DELAY ) self._started = True return util.StoppingContext(self) def stop(self): """ Restore settings and clean up. """ if not self._started: return # XXX which exceptions does this actually raise? EnvironmentError? try: self._close_connection() except Exception: pass signal.signal(signal.SIGTERM,signal.SIG_DFL) self._cleanup_pipe() self._started = False def set_input_timeouts(self, *args): pass def run_wrapper(self,fn): """ Run the application main loop, calling start() first and stop() on exit. """ try: self.start() return fn() finally: self.stop() def _close_connection(self): if self.update_method == "polling child": self.server_socket.settimeout(0) sock, addr = self.server_socket.accept() sock.sendall("Z") sock.close() if self.update_method == "multipart": sys.stdout.write("\r\nZ" "\r\n--ZZ--\r\n") sys.stdout.flush() def _cleanup_pipe(self, *args): if not self.pipe_name: return # XXX which exceptions does this actually raise? EnvironmentError? try: os.remove(self.pipe_name+".in") os.remove(self.pipe_name+".update") except Exception: pass def _set_screen_size(self, cols, rows ): """Set the screen size (within max size).""" if cols > MAX_COLS: cols = MAX_COLS if rows > MAX_ROWS: rows = MAX_ROWS self.screen_size = cols, rows def draw_screen(self, size, r ): """Send a screen update to the client.""" (cols, rows) = size if cols != self.last_screen_width: self.last_screen = {} sendq = [self.content_head] if self.update_method == "polling": send = sendq.append elif self.update_method == "polling child": signal.alarm( 0 ) try: s, addr = self.server_socket.accept() except socket.timeout: sys.exit(0) send = s.sendall else: signal.alarm( 0 ) send = sendq.append send("\r\n") self.content_head = "" assert r.rows() == rows if r.cursor is not None: cx, cy = r.cursor else: cx = cy = None new_screen = {} y = -1 for row in r.content(): y += 1 row = list(row) l = [] sig = tuple(row) if y == cy: sig = sig + (cx,) new_screen[sig] = new_screen.get(sig,[]) + [y] old_line_numbers = self.last_screen.get(sig, None) if old_line_numbers is not None: if y in old_line_numbers: old_line = y else: old_line = old_line_numbers[0] send( "<%d\n"%old_line ) continue col = 0 for (a, cs, run) in row: run = run.translate(_trans_table) if a is None: fg,bg,mono = "black", "light gray", None else: fg,bg,mono = self.palette[a] if y == cy and col <= cx: run_width = util.calc_width(run, 0, len(run)) if col+run_width > cx: l.append(code_span(run, fg, bg, cx-col)) else: l.append(code_span(run, fg, bg)) col += run_width else: l.append(code_span(run, fg, bg)) send("".join(l)+"\n") self.last_screen = new_screen self.last_screen_width = cols if self.update_method == "polling": sys.stdout.write("".join(sendq)) sys.stdout.flush() sys.stdout.close() self._fork_child() elif self.update_method == "polling child": s.close() else: # update_method == "multipart" send("\r\n--ZZ\r\n") sys.stdout.write("".join(sendq)) sys.stdout.flush() signal.alarm( ALARM_DELAY ) def clear(self): """ Force the screen to be completely repainted on the next call to draw_screen(). (does nothing for web_display) """ pass def _fork_child(self): """ Fork a child to run CGI disconnected for polling update method. Force parent process to exit. """ daemonize( self.pipe_name +".err" ) self.input_fd = os.open(self.pipe_name+".in", os.O_NONBLOCK | os.O_RDONLY) self.update_method = "polling child" s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) s.bind( self.pipe_name+".update" ) s.listen(1) s.settimeout(POLL_CONNECT) self.server_socket = s def _handle_alarm(self, sig, frame): assert self.update_method in ("multipart","polling child") if self.update_method == "polling child": # send empty update try: s, addr = self.server_socket.accept() s.close() except socket.timeout: sys.exit(0) else: # send empty update sys.stdout.write("\r\n\r\n--ZZ\r\n") sys.stdout.flush() signal.alarm( ALARM_DELAY ) def get_cols_rows(self): """Return the screen size.""" return self.screen_size def get_input(self, raw_keys=False): """Return pending input as a list.""" l = [] resized = False try: iready,oready,eready = select.select( [self.input_fd],[],[],0.5) except select.error as e: # return on interruptions if e.args[0] == 4: if raw_keys: return [],[] return [] raise if not iready: if raw_keys: return [],[] return [] keydata = os.read(self.input_fd, MAX_READ) os.close(self.input_fd) self.input_fd = os.open(self.pipe_name+".in", os.O_NONBLOCK | os.O_RDONLY) #sys.stderr.write( repr((keydata,self.input_tail))+"\n" ) keys = keydata.split("\n") keys[0] = self.input_tail + keys[0] self.input_tail = keys[-1] for k in keys[:-1]: if k.startswith("window resize "): ign1,ign2,x,y = k.split(" ",3) x = int(x) y = int(y) self._set_screen_size(x, y) resized = True else: l.append(k) if resized: l.append("window resize") if raw_keys: return l, [] return l def code_span( s, fg, bg, cursor = -1): code_fg = _code_colours[ fg ] code_bg = _code_colours[ bg ] if cursor >= 0: c_off, _ign = util.calc_text_pos(s, 0, len(s), cursor) c2_off = util.move_next_char(s, c_off, len(s)) return ( code_fg + code_bg + s[:c_off] + "\n" + code_bg + code_fg + s[c_off:c2_off] + "\n" + code_fg + code_bg + s[c2_off:] + "\n") else: return code_fg + code_bg + s + "\n" def html_escape(text): """Escape text so that it will be displayed safely within HTML""" text = text.replace('&','&') text = text.replace('<','<') text = text.replace('>','>') return text def is_web_request(): """ Return True if this is a CGI web request. """ return 'REQUEST_METHOD' in os.environ def handle_short_request(): """ Handle short requests such as passing keystrokes to the application or sending the initial html page. If returns True, then this function recognised and handled a short request, and the calling script should immediately exit. web_display.set_preferences(..) should be called before calling this function for the preferences to take effect """ global _prefs if not is_web_request(): return False if os.environ['REQUEST_METHOD'] == "GET": # Initial request, send the HTML and javascript. sys.stdout.write("Content-type: text/html\r\n\r\n" + html_escape(_prefs.app_name).join(_html_page)) return True if os.environ['REQUEST_METHOD'] != "POST": # Don't know what to do with head requests etc. return False if 'HTTP_X_URWID_ID' not in os.environ: # If no urwid id, then the application should be started. return False urwid_id = os.environ['HTTP_X_URWID_ID'] if len(urwid_id)>20: #invalid. handle by ignoring #assert 0, "urwid id too long!" sys.stdout.write("Status: 414 URI Too Long\r\n\r\n") return True for c in urwid_id: if c not in "0123456789": # invald. handle by ignoring #assert 0, "invalid chars in id!" sys.stdout.write("Status: 403 Forbidden\r\n\r\n") return True if os.environ.get('HTTP_X_URWID_METHOD',None) == "polling": # this is a screen update request s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) try: s.connect( os.path.join(_prefs.pipe_dir, "urwid"+urwid_id+".update") ) data = "Content-type: text/plain\r\n\r\n"+s.recv(BUF_SZ) while data: sys.stdout.write(data) data = s.recv(BUF_SZ) return True except socket.error: sys.stdout.write("Status: 404 Not Found\r\n\r\n") return True # this is a keyboard input request try: fd = os.open((os.path.join(_prefs.pipe_dir, "urwid"+urwid_id+".in")), os.O_WRONLY) except OSError: sys.stdout.write("Status: 404 Not Found\r\n\r\n") return True # FIXME: use the correct encoding based on the request keydata = sys.stdin.read(MAX_READ) os.write(fd,keydata.encode('ascii')) os.close(fd) sys.stdout.write("Content-type: text/plain\r\n\r\n") return True class _Preferences: app_name = "Unnamed Application" pipe_dir = "/tmp" allow_polling = True max_clients = 20 _prefs = _Preferences() def set_preferences( app_name, pipe_dir="/tmp", allow_polling=True, max_clients=20 ): """ Set web_display preferences. app_name -- application name to appear in html interface pipe_dir -- directory for input pipes, daemon update sockets and daemon error logs allow_polling -- allow creation of daemon processes for browsers without multipart support max_clients -- maximum concurrent client connections. This pool is shared by all urwid applications using the same pipe_dir """ global _prefs _prefs.app_name = app_name _prefs.pipe_dir = pipe_dir _prefs.allow_polling = allow_polling _prefs.max_clients = max_clients class ErrorLog: def __init__(self, errfile ): self.errfile = errfile def write(self, err): open(self.errfile,"a").write(err) def daemonize( errfile ): """ Detach process and become a daemon. """ pid = os.fork() if pid: os._exit(0) os.setsid() signal.signal(signal.SIGHUP, signal.SIG_IGN) os.umask(0) pid = os.fork() if pid: os._exit(0) os.chdir("/") for fd in range(0,20): try: os.close(fd) except OSError: pass sys.stdin = open("/dev/null","r") sys.stdout = open("/dev/null","w") sys.stderr = ErrorLog( errfile )