Kbase 20011: Sample Code To Access a Web Site via HTTP with 4GL Sockets
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
15/10/2008 |
|
Status: Verified
GOAL:
How to access a web site from 4GL
GOAL:
Implementing HTTP via 4GL sockets
GOAL:
4GL sockets client program
FACT(s) (Environment):
Progress 9.x
FIX:
This solution provides a sample program that shows how to access a web site using the Hypertext Transfer Protocol (HTTP) internet protocol with Progress 4GL.
The 4GL program retrieves a web page as a web browser would do and presents the corresponding text of the page.
You can use the following sample code as the starting point of a program to access a web site or as an example of how to use 4GL sockets in a client application.
The sockets routines that the Progress program uses are in an include file called httpget.i. This include file can be included in any program that requires the socket routine functionality.
The following program uses httpget.i and the httpget.i:
DEFINE VARIABLE wurl AS CHARACTER FORMAT "X(255)"
VIEW-AS FILL-IN SIZE 65 BY 1
INITIAL "http://www.progress.com/" LABEL "Url" NO-UNDO.
DEFINE VARIABLE weditor AS CHARACTER VIEW-AS EDITOR INNER-CHARS
72 INNER-LINES 32 LARGE SCROLLBAR-VERTICAL NO-UNDO.
DEFINE BUTTON b-get LABEL "GET".
DEFINE VARIABLE vhost AS CHARACTER NO-UNDO.
DEFINE VARIABLE vport AS CHARACTER NO-UNDO.
DEFINE VARIABLE vpath AS CHARACTER NO-UNDO.
DEFINE VARIABLE vfile AS CHARACTER NO-UNDO.
SESSION:APPL-ALERT-BOXES = YES.
FORM wurl b-get SKIP weditor NO-LABELS
WITH FRAME DEFAULT-FRAME THREE-D SIDE-LABELS.
ON 'RETURN':U OF wurl OR 'CHOOSE':U OF b-get
DO:
ASSIGN wurl.
RUN UrlParser(INPUT wurl, OUTPUT vhost, OUTPUT vport, OUTPUT vpath).
RUN HTTPGet(vhost, vport, vpath, vfile).
weditor:READ-FILE(vfile).
RETURN.
END.
RUN adecomm/_tmpfile.p ("i", ".htm", OUTPUT vfile).
MAIN-BLOCK:
DO ON ERROR UNDO MAIN-BLOCK, LEAVE MAIN-BLOCK
ON END-KEY UNDO MAIN-BLOCK, LEAVE MAIN-BLOCK:
DISPLAY wurl weditor WITH FRAME DEFAULT-FRAME.
ENABLE wurl b-get weditor WITH FRAME DEFAULT-FRAME.
WAIT-FOR GO OF CURRENT-WINDOW.
END.
OS-DELETE VALUE(vfile) NO-ERROR.
{ httpget.i }
/* *** */
/* Code for httpget.i */
DEFINE STREAM outfile.
DEFINE VARIABLE vSocket AS HANDLE NO-UNDO.
DEFINE VARIABLE wstatus AS LOGICAL NO-UNDO.
DEFINE VARIABLE vStr AS CHARACTER NO-UNDO.
DEFINE VARIABLE vBuffer AS MEMPTR NO-UNDO.
DEFINE VARIABLE wloop AS LOGICAL NO-UNDO.
PROCEDURE UrlParser:
DEFINE INPUT PARAMETER purl AS CHARACTER NO-UNDO.
DEFINE OUTPUT PARAMETER phost AS CHARACTER NO-UNDO.
DEFINE OUTPUT PARAMETER pport AS CHARACTER NO-UNDO.
DEFINE OUTPUT PARAMETER ppath AS CHARACTER NO-UNDO.
DEFINE VARIABLE vStr AS CHARACTER NO-UNDO.
IF purl BEGINS "http://" THEN
DO:
vStr = SUBSTRING(purl, 8).
phost = ENTRY(1, vStr, "/").
IF NUM-ENTRIES(vStr, "/") = 1 THEN vStr = vStr + "/".
ppath = SUBSTRING(vStr, INDEX(vStr,"/")).
IF NUM-ENTRIES(phost, ":") > 1 THEN
DO:
pport = ENTRY(2, phost, ":").
phost = ENTRY(1, phost, ":").
END.
ELSE
DO:
pport = "80".
END.
END.
ELSE
DO:
phost = "".
pport = "".
ppath = purl.
END.
END PROCEDURE.
PROCEDURE HTTPGet:
DEFINE INPUT PARAMETER phost AS CHARACTER NO-UNDO.
DEFINE INPUT PARAMETER pport AS CHARACTER NO-UNDO.
DEFINE INPUT PARAMETER ppath AS CHARACTER NO-UNDO.
DEFINE INPUT PARAMETER pfile AS CHARACTER NO-UNDO.
wloop = YES.
CREATE SOCKET vSocket.
vSocket:SET-READ-RESPONSE-PROCEDURE ("readHandler",THIS-PROCEDURE).
wstatus = vSocket:CONNECT("-H " + phost + " -S " + pport) NO-ERROR.
IF wstatus = NO THEN
DO:
MESSAGE "Connection to http server:" phost "port" pport
"is unavailable".
DELETE OBJECT vSocket.
RETURN.
END.
OUTPUT STREAM outfile TO VALUE(pfile) BINARY NO-CONVERT.
vStr = "GET " + ppath + " HTTP/1.0" + "~n~n~n".
SET-SIZE(vBuffer) = LENGTH(vStr) + 1.
PUT-STRING(vBuffer,1) = vStr.
vSocket:WRITE(vBuffer, 1, LENGTH(vStr)).
SET-SIZE(vBuffer) = 0.
WAIT-FOR CLOSE OF THIS-PROCEDURE.
vSocket:DISCONNECT().
DELETE OBJECT vSocket.
OUTPUT STREAM outfile CLOSE.
END PROC.EDURE.
PROCEDURE readHandler:
DEFINE VARIABLE l AS INTEGER NO-UNDO.
DEFINE VARIABLE str AS CHARACTER NO-UNDO.
DEFINE VARIABLE b AS MEMPTR NO-UNDO.
IF SELF:CONNECTED() = FALSE THEN
DO:
APPLY 'CLOSE' TO THIS-PROCEDURE.
RETURN.
END.
l = vSocket:GET-BYTES-AVAILABLE().
IF l > 0 THEN
DO:
SET-SIZE(b) = l + 1.
vSocket:READ(b, 1, l, 1).
str = GET-STRING(b,1).
PUT STREAM outfile CONTROL str.
SET-SIZE(b) = 0.
wloop = YES.
END.
ELSE
DO:
wloop = NO.
OUTPUT STREAM outfile CLOSE.
END.
END..