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=====Fetching a secure web page===== //by Richard Russell, July 2009//\\ \\ The procedure listed below fetches the contents of a secure (**https:**) web page to a specified file; it uses the [[|OpenSSL]] library and requires the files **libssl32.dll** and **libeay32.dll** to be available. They can be downloaded in this [[|Zip file]], from which they should be extracted and copied to a location where they will be found by **LoadLibrary**, i.e. one of:\\ * The directory from which the application will be loaded (@dir$). * The 'current' directory. * The system directory (e.g. **C:\Windows\System32\**). * The Windows directory (e.g. **C:\Windows\**). * One of the directories listed in the PATH environment variable. \\ If you want to distribute **libssl32.dll** and **libeay32.dll** with your application then store them in **@dir$** and embed them in the executable. Alternatively you can put them in **@lib$** (or a sub-directory) but in that case you will need to amend the procedure below to load them explicitly from that location.\\ \\ The procedure should be called in the following context:\\ \\ <code bb4w> port$ = "443" : REM https host$ = "" page$ = "/sslcheck.html" file$ = @tmp$ + "sslcheck.html" PROCsslfetch(port$, host$, page$, file$) </code> This fetches the page to the file **sslcheck.html**.\\ \\ Here is the procedure:\\ \\ <code bb4w> DEF PROCsslfetch(port$, host$, page$, file$) LOCAL libssl%, libeay%, meth%, ctx%, sock%, temp%, res%, ssl%, sbio%, file% LOCAL req$, buf&() FIONBIO = &8004667E BIO_NOCLOSE = 0 BUFSIZ = 256 ON ERROR LOCAL RESTORE ERROR : INSTALL @lib$+"SOCKLIB" PROC_initsockets SYS "LoadLibrary", "libssl32.dll" TO libssl% IF libssl% = 0 PROCsslcleanup : ERROR 100, "Cannot load LIBSSL32.DLL" SYS "GetProcAddress", libssl%, "SSL_library_init" TO `SSL_library_init` SYS "GetProcAddress", libssl%, "SSLv23_method" TO `SSLv23_method` SYS "GetProcAddress", libssl%, "SSL_CTX_new" TO `SSL_CTX_new` SYS "GetProcAddress", libssl%, "SSL_new" TO `SSL_new` SYS "GetProcAddress", libssl%, "SSL_set_bio" TO `SSL_set_bio` SYS "GetProcAddress", libssl%, "SSL_connect" TO `SSL_connect` SYS "GetProcAddress", libssl%, "SSL_write" TO `SSL_write` SYS "GetProcAddress", libssl%, "SSL_read" TO `SSL_read` SYS "GetProcAddress", libssl%, "SSL_CTX_free" TO `SSL_CTX_free` SYS "LoadLibrary", "libeay32.dll" TO libeay% IF libeay% = 0 PROCsslcleanup : ERROR 100, "Cannot load LIBEAY32.DLL" SYS "GetProcAddress", libeay%, "BIO_new_socket" TO `BIO_new_socket` REM Global system initialisation: SYS `SSL_library_init` REM Create SSL context: SYS `SSLv23_method` TO meth% SYS `SSL_CTX_new`, meth% TO ctx% IF ctx% = 0 PROCsslcleanup : ERROR 100, "SSL_CTX_new failed" REM Connect the TCP socket: sock% = FN_tcpconnect(host$, port$) IF sock% < 0 PROCsslcleanup : ERROR 100, "Cannot connect to " + host$ temp% = 0 SYS `ioctlsocket`, sock%, FIONBIO, ^temp% TO res% IF res% PROCsslcleanup : ERROR 105, "Cannot set socket to blocking" REM Connect the SSL socket: SYS `SSL_new`, ctx% TO ssl% SYS `BIO_new_socket`, sock%, BIO_NOCLOSE TO sbio% SYS `SSL_set_bio`, ssl%, sbio%, sbio% SYS `SSL_connect`, ssl% TO res% IF res% <= 0 PROCsslcleanup : ERROR 100, "SSL connect failed: " + STR$res% REM Request the page: req$ = "GET " + page$ + " HTTP/1.0" + CHR$13 + CHR$10 req$ += "User-Agent: BB4W" + CHR$13 + CHR$10 req$ += "Host: " + host$ + ":" + port$ + CHR$13 + CHR$10 req$ += CHR$13 + CHR$10 SYS `SSL_write`, ssl%, req$, LEN(req$) TO res% IF res% <> LEN(req$) PROCsslcleanup : ERROR 100, "SSL write failed: " + STR$res% REM Copy the requested page to a file: DIM buf&(BUFSIZ-1) file% = OPENOUT(file$) REPEAT SYS `SSL_read`, ssl%, ^buf&(0), BUFSIZ TO res% IF res% > 0 SYS "WriteFile", @hfile%(file%), ^buf&(0), res%, ^temp%, 0 UNTIL res% <= 0 CLOSE #file% IF res% PROCsslcleanup : ERROR 100, "SSL read failed: " + STR$res% REM Tidy up before exit: PROCsslcleanup ENDPROC DEF PROCsslcleanup sock% += 0 : IF sock% PROC_closesocket(sock%) : sock% = 0 ctx% += 0 : IF ctx% SYS `SSL_CTX_free`, ctx% : ctx% = 0 libssl% += 0 : IF libssl% SYS "FreeLibrary", libssl% : libssl% = 0 libeay% += 0 : IF libeay% SYS "FreeLibrary", libeay% : libeay% = 0 PROC_exitsockets ENDPROC </code>

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fetching_20a_20secure_20web_20page.1523981192.txt.gz · Last modified: 2018/04/17 17:06 by tbest3112