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To send emails.
When sending email, a number of optional parameters are supported.
| cc | to copy another recipient to receive the email. To cc more than 1 recipient, use multiple CC options: &cc=someone@somewhere.com&cc=someone_else@somewhere.com | |
| emailfrom | default to the email address in Outlook Express or the value of sheerpower$emailfrom | |
| replyto | to specify a "reply to" email address that is different from the emailfrom email address | |
| friendlyname | the name that is displayed to the recipient beside your email address | |
| server | default to the SMTP server used by Outlook Express or the value of the logical sheerpower$server | |
| wait | wait for email send to be completed | |
| nowait | queue the email for sending as time permits | |
| timeout | default is 30 second timeout. If we cannot reach the email server in this amount of time, abort the email sending. | |
| username and password | when the SMTP server requires authentication, use these parameters to enter the username and password. | |
| attach=file_to_attach.xxx | attach a file to this email. To attach more than one file, use multiple ATTACH options: attach=file1.xxx&attach=file2.xxx | |
| mime_type=html | specifies the email can be created in HTML format. If this parameter is not defined, the default of plain text email will be used. |
The start of the parameter list begins with a ? (question mark), and each parameter is separated by an & (ampersand). |
Emails are queued for sending when the file is closed. If WAIT was specified, then SheerPower waits until the email is delivered before continuing processing. The default is NOWAIT.
For high reliability on sending emails with SheerPower 4GL, the SMTP server should be either on the same server as SheerPower or at least on the same LAN. This is because the SheerPower 4GL email handler is not a full email system that endlessly tries to send out emails even if the application has terminated.
The best use for the SheerPower email facility is:
SheerPower --> SMTP server (local one) --> Internet for delivery
This way there will be very few delays and reliability will be highest.
SheerPower applications can easily be "web-enabled" through its simple CGI Interface. The CGI interface works with SheerPower's own webserver program, SPINS webserver. For more information on SPINS webserver, see Chapter 18, SheerPower Internet Services (SPINS) Webserver.
The sample CGI program eval_handler.spsrc is located in:
c:\sheerpower\sphandler |
The webpage instructions that go along with the sample program is located in the same folder, and is called cgi.html.
To use the CGI interface in SheerPower, SPINS Webserver must be running. If the Microsoft IIS webserver is running, it needs to be stopped, or ports configured to run both webservers at the same time. Instructions are found here - Section 18.1.3, Specify a Different Port Number.
To continue with this test, double-click on the EVAL_HANDLER.SPSRC file. This runs the EVAL_HANDLER program. This program file is located in:
c:\sheerpower\sphandlers\eval_handler.spsrc
After the EVAL_HANDLER has been started, you can try the FORM below.
If this form did not work correctly for you, see Appendix L, Troubleshooting the CGI Interface. |
Each time anyone enters an expression to evaluate (like 2+3), their browser sends the data to your SPINS webserver along with a handler name. In this example, the handler name is EVAL. The SPINS websever then passes the data to the EVAL_HANDLER.SPSRC SheerPower program. The EVAL_HANDLER handles the request, figures out the result, and sends the result back to the SPINS server. The SPINS server then sends the result back to the browser.
The handler name defined in the source code MUST be defined in UPPER CASE. |
In order to handle CGI requests, the following steps need to be taken:
First we open our CGI connection to the SPINS server.
handler_name$ = 'cgi://EVAL'
open file cgi_ch: name handler_name$
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In this example, EVAL is the HANDLER NAME.
Note that the handler name defined in the source code MUST be defined in UPPER CASE.
For higher performance, you can run as many copies of this handler as you wish. The SheerPower CGI interface will queue all requests to these handlers that have the form:
http://www.ttinet.com/scripts/spiis.dll/EVAL
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Next we set up a logic loop to wait for requests, handle timeouts, and process each request.
do
line input #cgi_ch: method$
if method$ = '' then repeat do
..
..
loop
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The LINE INPUT waits for a request from the SPINS server. When the LINE INPUT completes, the variable METHOD$ will contain one of three values.
In this program, when there is no request from the SPINS server (a timeout), we just go back and try again. In complex applications a program might instead unlock databases, write out statistics, and then go back and try again.
Now that we have a request from the SPINS server, we have to process the request.
ask #cgi_ch, symbol 'EXPR': value expr$
if expr$ = '' then
print #cgi_ch: '<h2>Thank you for using the Evaluator!</h2>'
repeat do
end if
when exception in
answer = eval(expr$)
use
answer = extext$
end when
if dtype(answer) <> 1 then answer = str$(answer)
print #cgi_ch: '<h2>'; expr$; ' --> '; answer; '</h2>'
ask #cgi_ch, symbol 'env:REMOTE_ADDR': value ipaddr$
print #cgi_ch: '(Your IP address is '; ipaddr$; ')'
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This form returns one form variable---the expression to be evaluated (EXPR). We use the SheerPower ASK instruction to ask for its value.
ask #cgi_ch, symbol 'EXPR': value expr$ |
If they didn't enter any expression, we just tell them "Thank you...". This is done using the PRINT instruction.
print #cgi_ch: '<h2>Thank you for using the Evaluator!</h2>'
Using EXPR$, we calculate the ANSWER and PRINT the result back to the SPINS server.
print #cgi_ch: '<h2>'; expr$; ' --> '; answer; '</h2>'
Finally, we ask the SPINS server for the "REMOTE_ADDR". This is the IP address of the requestor. Since "REMOTE_ADDR" is an environmental variable, we must put "env:" in front of the symbol name. Once we get the IP address, we PRINT it to the SPINS server---which, in turn, sends the data back to the browser.
ask #cgi_ch, symbol 'env:REMOTE_ADDR': value ipaddr$ print #cgi_ch: '(Your IP address is '; ipaddr$; ')' |
By default, SheerPower automatically builds the CGI required HTTP headers. But, sometimes there is a need to write out your own custom HTTP headers. For example, you might need to write out binary data, or perhaps send a cookie. Here is a sample routine that writes out a HTTP header:
routine start_http_output
ask #cgi_ch, symbol 'env:PATH_INFO': value path_info$
print #cgi_ch: "HTTP/1.1 200 OK"
print #cgi_ch: 'Cache-Control: max-age=2, must-revalidate'
print #cgi_ch: "Content-type: text/html"
print #cgi_ch: 'Referer: ' + path_info$
print #cgi_ch: "Pragma: no-cache"
print #cgi_ch:
print #cgi_ch:
end routine
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When printing out binary data, include a trailing semi-colon at the end of the PRINT instruction: print #cgi_ch: mybinary$; // notice the trailing semi-colon |
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