MODULEvocgi - gateway for visual obliq.; Main
This is responsible for a variety of operations that result in the creation of an html page on the fly to support distributed apps on the world-wide web.
KEYWORDS (voapps, vosessions, voget, vojoin, vomembers)
USAGE:
.../vocgi/<DIR>?voapps+<HOSTNAME>
= generates a list of available apps in a certain directory with html links. Clicking on the name of an app will cause it to be registered with a network object called voWebList@<HOSTNAME> and will import the text of the program.
Apps are identified by the vobl extension.
The apps are listed as follows:-
<app-name>(description) --- Link1-- --Link2--
Link1 = .../vocgi/<FULLPATH>/app.vobl?voget+<HOSTNAME> Link2 = <FULLPATH>/app.html This is created only if the html file is present
.../vocgi?vosessions+<HOSTNAME>
= generates a list of ongoing sessions registered with vowwwlist@<HOSTNAME> with html links. Names of sessions are listed as
<app-name>@<server-sitename> (description, members) --------- Link1------------ --Link2-- -Link3-
Link1 = .../vocgi?vojoin+<app-name>@<server-sitename> Link2 = <FULLPATH>/app.html ( if present ) Link3 = .../vocgi?vomembers+<app-name>@<server-sitename>
.../vocgi/<FULLPATH>/app.vobl?voget+<HOSTNAME>
= sends the vobl file over as plaintext and registers the server site name with voWebList@<HOSTNAME>
.../vocgi?vojoin+<app-name>@<server-sitename>
= returns vojoin <app-name>@<server-sitename>;
.../vocgi?vomembers+<app-name>@<server-sitename>
= queries <app-name>@<server-sitename> for the list of participants and then sees if they are alive and generates a list of active members.
IMPORT Obliq, ObValue; IMPORT ObliqOnline; IMPORT ObLibM3; (* rd,wr,lex,fmt,pickle,process,thread *) IMPORT Env, File, FileRd, FS, OSError, Params, Pathname, Rd; IMPORT SynWr, Text, TextList, TextRd, TextWr, Thread, Wr; FROM Stdio IMPORT stdout; EXCEPTION InputError(TEXT); CONST Greetings = ""; IntroToApps = "<i>This page lists a set of Visual Obliq Applications " & "that may be invoked by clicking on corresponding links. Imported " & "applications are run within a 'safe' Visual Obliq Interpreter on " & "your site. Whenever the imported program tries to access a file " & "or spawn a process you will be notified and allowed to abort it, " & "unless the action is allowed in your </i>.vorestrict<i> file.</i>" & "<P><P>\n"; VAR interp: ObliqOnline.T;
rsrcPath : Rsrc.Path;
output := TextWr.New(); PROCEDUREEnumerate (fn: TEXT): TextList.T RAISES {OSError.E} = VAR res, tail, l: TextList.T := NIL; t: TEXT; i: FS.Iterator; BEGIN IF fn = NIL THEN fn := ""; END; TRY i := FS.Iterate(fn); WHILE i.next(t) DO l := TextList.Cons(t, NIL); IF res = NIL THEN res := l; ELSE tail.tail := l; END; tail := l; END; FINALLY i.close(); END; RETURN res; END Enumerate; PROCEDUREGetEnv (s : TEXT) : TEXT = BEGIN WITH z = Env.Get(s) DO IF s = NIL THEN RETURN(""); ELSE RETURN(z); END (* IF *) END (* WITH *) END GetEnv; VAR vopath := GetEnv("PATH_INFO"); voclient := GetEnv("REMOTE_HOST"); PROCEDUREDo (cmd: TEXT; name : TEXT := "current file")= BEGIN ObliqOnline.Interact(interp, rd := TextRd.New(cmd), rdName := name, closeRd := TRUE, generateEOF := TRUE); END Do;
PROCEDURE LoadObliqRsrc(name: TEXT) =
BEGIN
TRY
WITH loadedFile = Rsrc.Get(name, rsrcPath) DO
Do(loadedFile, name);
END;
EXCEPT
Rsrc.NotFound =>Error(Cannot find '
, name, ' in resource bundle
);
ELSE
Error(While executing '
, name, '
);
END (* TRY
; END LoadObliqRsrc; *) PROCEDURE------------------------------------------------ errors & low-level I/O ---StartInterpreter () = BEGIN (* rsrcPath := Rsrc.BuildPath ("$VOCGIPATH", VOCgiBundle.Get()); *) ObliqOnline.Setup(); ObLibM3.PackageSetup(); interp := ObliqOnline.New(Greetings, SynWr.New(output), FALSE); (* Dont load default .obliq - who knows what it contains *) (* Instead use bundled files *) Do(";"); END StartInterpreter; PROCEDUREMakeHtmlLink (message, linkto : TEXT) : TEXT = BEGIN RETURN "<A HREF=\"" & linkto & "\">" & message & "</A>"; END MakeHtmlLink; PROCEDUREVOApps () RAISES { InputError } = BEGIN (* open vopath as a directory and list all the vobl files therein *) Out ("Content-type: text/html\n\n\n"); Out ("<TITLE>List of Available Applications</TITLE>\n<UL>\n"); Out ("<H2>Visual Obliq Applications</H2>\n"); Out ("(Generated automatically by the gateway, "); Out (Params.Get(0), ")<P><P>\n"); Out (IntroToApps); TRY WITH enumlist = Enumerate(vopath) DO FOR i := 0 TO TextList.Length(enumlist) DO WITH current = TextList.Nth(enumlist, i), ext = Pathname.LastExt(current), registerAt = Params.Get(2) DO IF Text.Equal(ext, "vobl") THEN (* Out ("<LI> ", MakeHtmlLink(Pathname.Base(current)); *) (* Out ("file://localhost", vopath, "/" & current)); *) Out ("<LI> "); Out (MakeHtmlLink(Pathname.Base(current), "https://" & GetEnv("SERVER_NAME") & GetEnv("SCRIPT_NAME") & vopath & "/" & current & "?voget+" & registerAt )); (* check if the corresponding file with a .html extension exists this will have the documentation *) WITH doc = vopath & "/" & Pathname.Base(current) & ".html" DO IF FileIsReadable(doc) THEN Out (" (", MakeHtmlLink("documentation", "file://localhost" & doc), " ) "); END END (* WITH *); Out ("<P>\n"); END (* IF *) END (* WITH *) END (* FOR *) END EXCEPT ELSE RAISE InputError("Could not open directory: " & vopath); END; END VOApps; PROCEDUREFileIsReadable (path: TEXT): BOOLEAN = VAR f: File.T; BEGIN TRY f := FS.OpenFileReadonly (path); f.close (); RETURN TRUE; EXCEPT OSError.E => RETURN FALSE; END; END FileIsReadable; PROCEDUREVOGet () = <*FATAL OSError.E, Rd.Failure, Wr.Failure, Thread.Alerted*> VAR f := FileRd.Open(vopath); (* vopath has the file in question *) oblcode := Rd.GetText(f, LAST(CARDINAL)); name := Pathname.LastBase(vopath); cmd := "try\n" & " let svr = net_import(\"vossns\", \"" & Params.Get(2) & "\");\n" & " svr.addNew(\"" & name & "\",\"" & voclient & "\");\n" & "except else end;\n"; BEGIN StartInterpreter(); (* register the <app>@<voclient> with the vossns@<Params.Get(2)> *) Do( cmd ); Out ("Content-type: application/x-vobl\n\n\n"); Out (oblcode); Wr.Flush(stdout); END VOGet; PROCEDUREVOJoin () = BEGIN WITH ssn = Params.Get(2), host = Params.Get(3) DO Out ("Content-type: application/x-vobl\n\n\n"); Out ("Join(\"" & ssn & "\",\"" & host & "\");\n"); END (* WITH *) END VOJoin; PROCEDUREVOSessions () = VAR quotedPrefix := "\"https://" & GetEnv("SERVER_NAME")&GetEnv("SCRIPT_NAME") & vopath & "?vojoin\""; script := "let result = \n" & "try\n" & " let svr = net_import(\"vossns\", \"" & Params.Get(2) & "\");\n" & " svr.genListing(" & quotedPrefix & ");\n" & "except else \"none\" end;\n"; BEGIN StartInterpreter(); Do(script); TRY WITH obval = Obliq.Lookup("result", interp.env), result = Obliq.ToText(obval) DO IF Text.Equal(result, "none") THEN Error("Couldn't get session listing from vossns@" & Params.Get(2) ); ELSE (* result should contain the complete html document *) Out (result); Wr.Flush(stdout); END (* IF *) END (* WITH *); EXCEPT ObValue.Error(foo) =>Error("POST-MORTEM = Raised Exception: " & foo.msg); ELSE END (* TRY *) END VOSessions;
PROCEDURE---------------------------------------------------------- main program ---Error (msg: TEXT) = BEGIN Out ("Content-type: text/html\n\n\n"); Out ("<H1>Error in " & Params.Get(0) & "</H1><P>\n"); Out ("<H2>" & msg & "</H2> <P>\n"); END Error; PROCEDUREUsageError (msg: TEXT) = BEGIN Error (msg); Out ("<H1>Usage:</H1> <P>\n<B>", Params.Get(0), "</B>\n"); Out ("[voapps < HOSTNAME> <P>"); Out ("| vosessions <HOSTNAME><P><UL><UL>\n"); Out (" | voget <HOSTNAME><P>"); Out (" | vojoin <APP-NAME>@<SERVER-SITENAME><P>\n"); Out (" | vomembers <APP-NAME>@<SERVER-SITENAME>] <P>\n"); END UsageError; PROCEDUREOut (a, b, c: TEXT := NIL) = <*FATAL Wr.Failure, Thread.Alerted*> BEGIN IF (a # NIL) THEN Wr.PutText (stdout, a); END; IF (b # NIL) THEN Wr.PutText (stdout, b); END; IF (c # NIL) THEN Wr.PutText (stdout, c); END; END Out;
BEGIN TRY IF Params.Count < 2 THEN UsageError("No arguments!"); ELSIF Params.Count <= 4 THEN WITH action = Params.Get(1) DO IF Text.Equal(action, "voapps") THEN (* open directory and list files with a vobl extension *) VOApps(); ELSIF Text.Equal(action, "vosessions") THEN VOSessions(); ELSIF Text.Equal(action, "voget") THEN VOGet(); ELSIF Text.Equal(action, "vojoin") THEN VOJoin(); ELSIF Text.Equal(action, "vomembers ") THEN UsageError("Unimplemented"); ELSE UsageError("Unknown command"); END END (* WITH *) ELSE UsageError("Argument list has too few or too many arguments"); END (* IF *) EXCEPT | InputError(t) => Error(t); ELSE Error("Error!"); END; END Main.