Networking¶
Unicon Networking¶
Ahh, the network. Unicon fully supports client server computing using standard words and phrases.
Note
Update: Nov 16 2016
Unicon has been setup to run on SourceForge. CGI and other browser friendly demonstrations will be posted. For instance:
Network mode¶
The open emphatic is used to initiate networking subsystems.
Network mode n
is the network client mode of open.
Network mode na
is network accept (blocking server) mode of open.
Network mode nl
is network listen (non-blocking server) mode of open.
Protocols include:
- TCP Transmission Control Protocol
- UDP User Datagram Protocol (add
u
to the open mode; for example “nua” for a blocking UDP server)
Message mode¶
Message mode m
is a special network mode of open. This is the web
as seen from Unicon. Support for http and https. Use m-
for less secure
but functional unauthenticated https, until local certificates are configured.
HTTP¶
HyperText Transport Protocol. A text based protocol used in much of the modern web.
Unicon handles HTTP by using open with a mode of m
(or ms
if
only HTTP headers are needed, and no page data).
#
# http.icn
#
procedure main()
# pull in the page
url := "http://example.com"
web := open(url, "m") | stop("Can't open " || url)
page := ""
while page ||:= read(web) || "\n"
# pull out any title
page ? {
tab(find("<title")) & tab(find(">")) & move(1) &
title := tab(find("</title"))
}
close(web)
# display the title, if any, and then the page
write("Page title: ", \title)
write(page)
end
Giving:
Page title: Example Domain
<!doctype html>
<html>
<head>
<title>Example Domain</title>
<meta charset="utf-8" />
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<style type="text/css">
body {
background-color: #f0f0f2;
margin: 0;
padding: 0;
font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
}
div {
width: 600px;
margin: 5em auto;
padding: 2em;
background-color: #fdfdff;
border-radius: 0.5em;
box-shadow: 2px 3px 7px 2px rgba(0,0,0,0.02);
}
a:link, a:visited {
color: #38488f;
text-decoration: none;
}
@media (max-width: 700px) {
div {
margin: 0 auto;
width: auto;
}
}
</style>
</head>
<body>
<div>
<h1>Example Domain</h1>
<p>This domain is for use in illustrative examples in documents. You may use this
domain in literature without prior coordination or asking for permission.</p>
<p><a href="https://www.iana.org/domains/example">More information...</a></p>
</div>
</body>
</html>
HTTPS¶
Secure (encrypted) HTTP. The text based HTTP protocol wrapped in encrypted packets. These packets use TLS and/or SSL encryption technology, a certificate based key pairing. An initial usually verified certificate is hosted by the server and temporary tokens are delivered to the client (browser) for single pair communications. This avoids clear text messaging, a rather easy thing to eavesdrop on, and or change in transit.
As of early Unicon 13 alpha releases, HTTPS is not quite ready. The
encryption works, once setup. It is the setup that is not quite ready. It is
not the smooth setup that will eventually be part of Unicon builds. There is
internal certificate management issues that may require end user intervention.
It will be advertised as ready when a basic build of Unicon does not require
any extraordinary effort on behalf of a Unicon programmer. For example, the
sample below required an externally set SSL_CERT_DIR
environment variable
before Jafar fixed the search path settings in SVN revision 4474 of the Unicon
code base.
Note
Leaving the sample in, as it doesn’t “hurt”, but this override is no longer required (at least for Ubuntu based Unicon built from source).
#
# https.icn, read and show a secure webpage, extract title
#
procedure main()
local url, web, page, title
# pull in the page
url := "https://example.com"
web := open(url, "m-") | stop("Can't open " || url)
page := ""
while page ||:= read(web) || "\n"
# pull out any title
page ? {
tab(find("<title")) & tab(find(">")) & move(1) &
title := tab(find("</title"))
}
close(web)
# display the title, if any, and then the page
write("Page title: ", \title)
write(page)
end
prompt$ SSL_CERT_DIR=/usr/lib/ssl/certs unicon https-full.icn -x
Parsing https-full.icn: .
/home/btiffin/unicon-git/bin/icont -c -O https-full.icn /tmp/uni74864738
Translating:
https-full.icn:
main
No errors
/home/btiffin/unicon-git/bin/icont https-full.u -x
Linking:
Executing:
Page title: Example Domain
<!doctype html>
<html>
<head>
<title>Example Domain</title>
<meta charset="utf-8" />
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<style type="text/css">
body {
background-color: #f0f0f2;
margin: 0;
padding: 0;
font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
}
div {
width: 600px;
margin: 5em auto;
padding: 2em;
background-color: #fdfdff;
border-radius: 0.5em;
box-shadow: 2px 3px 7px 2px rgba(0,0,0,0.02);
}
a:link, a:visited {
color: #38488f;
text-decoration: none;
}
@media (max-width: 700px) {
div {
margin: 0 auto;
width: auto;
}
}
</style>
</head>
<body>
<div>
<h1>Example Domain</h1>
<p>This domain is for use in illustrative examples in documents. You may use this
domain in literature without prior coordination or asking for permission.</p>
<p><a href="https://www.iana.org/domains/example">More information...</a></p>
</div>
</body>
</html>
Without the external certificate finder, the program does did not function properly.
Now, the environment setting is not necessary.
prompt$ unicon https-full.icn -x
Parsing https-full.icn: .
/home/btiffin/unicon-git/bin/icont -c -O https-full.icn /tmp/uni74864738
Translating:
https-full.icn:
main
No errors
/home/btiffin/unicon-git/bin/icont https-full.u -x
Linking:
Executing:
Page title: Example Domain
<!doctype html>
<html>
<head>
<title>Example Domain</title>
<meta charset="utf-8" />
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<style type="text/css">
body {
background-color: #f0f0f2;
margin: 0;
padding: 0;
font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", "Open Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
}
div {
width: 600px;
margin: 5em auto;
padding: 2em;
background-color: #fdfdff;
border-radius: 0.5em;
box-shadow: 2px 3px 7px 2px rgba(0,0,0,0.02);
}
a:link, a:visited {
color: #38488f;
text-decoration: none;
}
@media (max-width: 700px) {
div {
margin: 0 auto;
width: auto;
}
}
</style>
</head>
<body>
<div>
<h1>Example Domain</h1>
<p>This domain is for use in illustrative examples in documents. You may use this
domain in literature without prior coordination or asking for permission.</p>
<p><a href="https://www.iana.org/domains/example">More information...</a></p>
</div>
</body>
</html>
Verify¶
Messaging mode (open mode “m”) with https
adds a new, optional,
-
flag, for skipping certificate verification. The default is to try and
validate a certificate. "m"
is more secure than "m-"
, but does
require some external setup for certificate pairing. Otherwise the system will
block access with:
cannot verify peer's certificate
When validation fails, open will fail.
More HTTPS¶
The Unicon project is on SourceForge. And the Allura system that makes up most of the forge user interface supports a rich API.
To get the download counts for Unicon, using Unicon:
#
# https-json.icn, Try HTTPS with a SourceForge JSON query
#
# tectonics:
# unicon -s https-json.icn -x | jq .downloads[-4:-1]
#
procedure main()
uri := "https://sourceforge.net/projects/unicon/files/stats/json" ||
"?start_date=2010-10-01&end_date=2110-10-01"
web := open(uri, "m-") | stop("Can't open ", uri)
showHeaders(web)
size := 0 < integer(web["Content-Length"]) | stop("can't get the file size")
data := reads(web, size) | stop("failed to reads ", size, " bytes")
write(data)
close(web)
end
# write HTTPS response headers to standard error
procedure showHeaders(m)
local k
every k := key(\m) do write(&errout, left(k||":", 32), m[k])
end
That program will pull down a JSON response from SourceForge. The captured
command output asks jq
(JSON query) for the last entry from the
downloads
list from the data displayed by Unicon. Web server response
headers are also displayed from Unicon, directed to standard error to not
interfere with the JSON data passed to the jq
command. The capture
only includes a limited range of the header lines from the output, hence the
ellipsis.
prompt$ unicon -s https-json.icn -x | jq .downloads[-4:-1]
Status-Code: 200
Reason-Phrase: OK
Server: nginx/1.14.0 (Ubuntu)
Date: Fri, 25 Oct 2019 17:23:14 GMT
...
[
[
"2019-07-01 00:00:00",
74
],
[
"2019-08-01 00:00:00",
54
],
[
"2019-09-01 00:00:00",
47
]
]
CGI¶
There is a Technical Report (UTR4a 2011/02/04) Writing CGI and PHP
Scripts in Icon and Unicon
that details and lists working samples of
Common Gateway Interface
programming with Unicon. Methods for
integrating Unicon with PHP
is also explained.
http://unicon.org/utr/utr4.html
A CGI support layer is built along with unicon
, so programmers only need to
link cgi
to take advantage of CGI features.
There is a small sample now hosted on SourceForge, to show off a very simple
Unicon CGI program. simple-cgi.icn
can be tried using a form posted at:
http://btiffin.users.sourceforge.net/form.html
form-cgi.html
<!-- Simple Unicon CGI example form -->
<HTML>
<HEAD>
<title>A Unicon HTML Form Example</title>
<style type="text/css">
body {
background-color: #f0f0f2;
margin: 12;
padding: 4;
font-family: "Open Sans", "Helvetica Neue", Helvetica,
Arial, sans-serif;
}
div {
width: 600px;
margin: 5em auto;
padding: 50px;
background-color: #fff;
border-radius: 1em;
}
a:link, a:visited {
color: #38488f;
text-decoration: none;
}
@media (max-width: 700px) {
body {
background-color: #fff;
}
div {
width: auto;
margin: 0 auto;
border-radius: 0;
padding: 1em;
}
}
</style>
</HEAD>
<BODY>
<h1> A <tt>cgi.icn</tt> Demonstration</h1>
<form method="GET" action="/cgi-bin/simple.cgi">
1. Name: <input type="text" name="name" size=25> <p>
2. Age: <input type="text" name="age" size=3> Years <p>
3. Quest:
<input type="checkbox" name="fame">Fame</input>
<input type="checkbox" name="fortune">Fortune</input>
<input type="checkbox" name="grail">Grail</input><p>
4. Favorite Color:
<select name="color">
<option>Red
<option>Green
<option>Blue
<option selected>Don't Know (Aaagh!)
</select><p>
Comments:<br>
<textarea rows=5 cols=60 name="comments"></textarea><p>
<input type="submit" value="Submit Data">
<input type="reset" value="Reset Form">
</form>
</BODY>
</HTML>
That form invokes:
simple-cgi.icn
#
# simple-cgi.icn
# tectonics:
# unicon -B simple-cgi.icn
# mv simple ../cgi-bin/simple.cgi
#
link cgi
procedure cgimain()
# set defaults for both CGI and AJAX usage
if /cgi["name"] | cgi["name"] === "" then cgi["name"] := "Guest"
if /cgi["age"] | cgi["age"] === "" then cgi["age"] := "no"
if /cgi["comments"] then cgi["comments"] := ""
if /cgi["word"] then cgi["word"] := ""
# remove any potentially dangerous characters
cgi["name"] := map(cgi["name"], "<>&%", "....")
cgi["age"] := map(cgi["age"], "<>&%", "....")
cgi["comments"] := map(cgi["comments"], "<>&%", "....")
cgi["word"] := map(cgi["word"], "<>&%", "....")
# output for the web
cgiEcho("Hello, ", cgi["name"], "!")
cgiEcho("Are you really ", cgi["age"], " years old?")
cgiEcho("You seek: ", cgi["fame"]==="on" & "fame")
cgiEcho("You seek: ", cgi["fortune"]==="on" & "fortune")
cgiEcho("You seek: ", cgi["grail"]==="on" & "grail")
cgiEcho("Your favorite color is: ", cgi["color"])
cgiEcho("Your comments: ", cgi["comments"])
cgiEcho("")
cgiEcho("Your AJAX word: ", cgi["word"])
cgiEcho("")
cgiEcho("<a href=\"/demos/\">Home</a> / " ||
"<a href=\"/demos/simple-form.html\">Back to HTML form</a> / " ||
"<a href=\"/demos/simple-ajax.html\">Back to AJAX form</a>")
end
Unicon was built on a SourceForge hosted CentOS server using a Developer Web Services shell. Details of how this was set up is documented in a blog entry, SourceForge. There will be more examples posted. An index page will be placed at
http://btiffin.users.sourceforge.net/demos/index.html
CGI 1.1¶
The full CGI 1.1 specification is referenced in RFC3875,
AJAX¶
The simple.cgi
demo can also be put to work with an AJAX interface.
<!-- simple-ajax.html, Unicon AJAX example -->
<html>
<head>
<title>Simple AJAX Example with Unicon</title>
<script language="Javascript">
function xmlhttpPost(strURL) {
var xmlHttpReq = false;
var self = this;
// Mozilla/Safari
if (window.XMLHttpRequest) {
self.xmlHttpReq = new XMLHttpRequest();
}
// IE
else if (window.ActiveXObject) {
self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
}
self.xmlHttpReq.open('POST', strURL, true);
self.xmlHttpReq.setRequestHeader('Content-Type',
'application/x-www-form-urlencoded');
self.xmlHttpReq.onreadystatechange = function() {
if (self.xmlHttpReq.readyState == 4) {
updatepage(self.xmlHttpReq.responseText);
}
}
self.xmlHttpReq.send(getquerystring());
}
<!-- pass the form query -->
function getquerystring() {
var form = document.forms['form1'];
var word = form.word.value;
var name = form.name.value;
var age = form.age.value;
qstr = 'word=' + escape(word) + '&name=' + escape(name) +
'&age=' + escape(age);
return qstr;
}
<!-- change the result DOM div -->
function updatepage(str){
document.getElementById("result").innerHTML = str;
}
</script>
</head>
<body>
An asynchronous Javascript to Unicon example.<br>
Pressing <b>Go</b> will cause an AJAX call to the server,
and CGI results will appear below
<form name="form1">
<p>Name: <input name="name" type="text" size="25"></p>
<p> Age: <input name="age" type="text" size="2"></p>
<p>word: <input name="word" type="text">
<input value="Go" type="button"
onclick='javascript:xmlhttpPost("/cgi-bin/simple.cgi")'></p>
<div id="result"></div>
</form>
</body>
</html>
That AJAX example invokes the same server side simple-cgi.icn
as the CGI
form. The server side program is not a CGI application in this case, and there
is not the same set of environment variables that a web server will set up for
CGI programs, but the example program accounts for this to produce AJAX ready
output.
PHP¶
PHP (initially PHP/FI, Personal Home Page/Forms Interpreter, now know as PHP: Hypertext Preprocessor) is a widely used server side scripting language. PHP was never really meant to be a programming language, but has attained a lead position as a tool of choice for many web applications.
“I don’t know how to stop it, there was never any intent to write a programming language […] I have absolutely no idea how to write a programming language, I just kept adding the next logical step on the way.”
—Rasmus Lerdorf
Unicon can leverage that unstoppable project. PHP is almost always available along side any web server install, and is a feature rich and well supported web development environment.
Todo
add Unicon, PHP integration sample
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