User:Emily/Prototyping/Trimester 03/03: Difference between revisions
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CGI Basics | |||
: understanding--> set up the HTTP server so that whatever a file in a certain directory is requested that file is not sent back instead it is executed as a program, and whatever that program outputs is sent back for your browser to display("Content-Type: text/html"). | |||
:CGI programs can be python script, shell script, perl, c or c++ program ... | |||
:Get Method | |||
::url--> | |||
<source lang=python> | |||
"content-type: text/html\r\n\r\n" | |||
print "<h2> Hello %s %s</h2>" % (first_name, last_name) | |||
</source> | |||
::form--> | |||
<source lang=python> | |||
<form action="..." method="get"> | |||
<input type="text" name="..." /> | |||
<input type="submit" value="submit" /> | |||
</form> | |||
</source> | |||
:Post Method (send information as separate message instead of a text string) | |||
::form--> | |||
<source lang=python> | |||
<form action="..." method="post">... </form> | |||
</source> | |||
::checkbox--> | |||
<source lang=python> | |||
<form action="..." method="post" target="_blank"> | |||
<input type="checkbox" name="..." value="on"/> | |||
<input type="submit" value="submit" /> | |||
</form> | |||
</source> | |||
::radio button--> | |||
<source lang=python> | |||
<form action="..." method="post" target="_blank"> | |||
<input type="radio" name="..." value="on"/> | |||
<input type="submit" value="submit" /> | |||
</form> | |||
</source> | |||
::TextArea--> | |||
<source lang=python> | |||
<form action="..." method="post" target="_blank"> | |||
<textarea name="textcontent" cols="40" rows="4"/> type your text here </textarea><input type="submit" value="submit" /> | |||
</form> | |||
</source> | |||
::drop down box--> | |||
<source lang=python> | |||
<form action="/cgi-bin/dropdown.py" method="post" target="_blank"> | |||
<select name="dropdown"> | |||
<option value="Maths" selected>Maths</option> | |||
<option value="Physics">Physics</option> | |||
</select> | |||
<input type="submit" value="Submit"/> | |||
</form> | |||
</source> | |||
:CGI | |||
<source lang=python> | |||
#!/usr/bin/python | |||
# Import modules for CGI handling | |||
import cgi, cgitb | |||
# Create instance of FieldStorage | |||
form = cgi.FieldStorage() | |||
# Get data from fields | |||
if form.getvalue('dropdown'): | |||
subject = form.getvalue('dropdown') | |||
else: | |||
subject = "Not entered" | |||
print "Content-type:text/html\r\n\r\n" | |||
print "<html>" | |||
print "<head>" | |||
print "<title>Dropdown Box - Sixth CGI Program</title>" | |||
print "</head>" | |||
print "<body>" | |||
print "<h2> Selected Subject is %s</h2>" % subject | |||
print "</body>" | |||
print "</html>" | |||
</source> | |||
:cookies | |||
:file upload | |||
:file download | |||
---- | |||
HTTP server -- programs (CGI scripts) -- interface (user input submitted through HTML<form>or<isindex>element) --> generate web content | |||
python -m CGIHTTPSever | python -m CGIHTTPSever | ||
---- | ---- | ||
web server | ===== structure of CGI ===== | ||
:web server, processes requests via HTTP (Hypertext Transfer Protocol) | |||
:process user input submitted through an HTML <FORM> or <ISINDEX> element | :process user input submitted through an HTML <FORM> or <ISINDEX> element | ||
: cgi_directories [' /cgi-bin', ' /htbin'] containing CGI scripts | :cgi_directories [' /cgi-bin', ' /htbin'] containing CGI scripts (server's special cgi-bin directory) | ||
: CGI script consists of two sections, separated by a blank line. | :output - CGI script consists of two sections, separated by a blank line. | ||
print "Content-Type: text/html" #header, telling what kind of data is following | print "Content-Type: text/html" # header, telling what kind of data is following (HTML is following) | ||
print # blank line, end of headers | |||
print "<TITLE>CGI script output</TITLE>" | print "<TITLE>CGI script output</TITLE>" | ||
print "Hello Morld" #html, nice formatting | print "Hello Morld" #html, nice formatting | ||
cgi module | ===== using cgi module ===== | ||
import cgitb | import cgitb | ||
cgitb.enable() | cgitb.enable() # display detailed reports in web browser | ||
cgitb.enable(display=0, logdir="/path/to/logdir") #have the reports saved to files | |||
FieldStorage class | ===== to get at submitted form data ==== | ||
FieldStorage class --> can be indexed like a Python dictionary (in operator; support the standard dictionary method keys(), and built-in function len()) | |||
form = cgi.FieldStorage() | form = cgi.FieldStorage() | ||
If a field represents an uploaded file | the following code checks that the fields are set to a non-empty string | ||
<source lang=python> | |||
if "***" not in form or "###" not in form: | |||
print "Error" | |||
print "please fill in *** and ### fields" | |||
return | |||
print "<p>***:", form["***"].value | |||
print "<p>###:", form["###"].value | |||
</source> | |||
if the submitted form data contains more than one field with the same name -->form[key] is not a FieldStorage or MiniFieldStorage instance but a list of such instances; form.getvalue(key) return a list of strings; getlist()method, always returns a list of values | |||
value = form.getlist("username") | |||
usernames = ",".join(value) | |||
If a field represents an uploaded file ???? | |||
fileitem = form["userfile"] | fileitem = form["userfile"] | ||
| Line 35: | Line 135: | ||
Link: https://docs.python.org/2/library/cgi.html | Link: https://docs.python.org/2/library/cgi.html | ||
:https://pzwiki.wdka.nl/mediadesign/How_am_I_being_served | |||
Latest revision as of 14:48, 4 May 2015
CGI Basics
- understanding--> set up the HTTP server so that whatever a file in a certain directory is requested that file is not sent back instead it is executed as a program, and whatever that program outputs is sent back for your browser to display("Content-Type: text/html").
- CGI programs can be python script, shell script, perl, c or c++ program ...
- Get Method
- url-->
"content-type: text/html\r\n\r\n"
print "<h2> Hello %s %s</h2>" % (first_name, last_name)
- form-->
<form action="..." method="get">
<input type="text" name="..." />
<input type="submit" value="submit" />
</form>
- Post Method (send information as separate message instead of a text string)
- form-->
<form action="..." method="post">... </form>
- checkbox-->
<form action="..." method="post" target="_blank">
<input type="checkbox" name="..." value="on"/>
<input type="submit" value="submit" />
</form>
- radio button-->
<form action="..." method="post" target="_blank">
<input type="radio" name="..." value="on"/>
<input type="submit" value="submit" />
</form>
- TextArea-->
<form action="..." method="post" target="_blank">
<textarea name="textcontent" cols="40" rows="4"/> type your text here </textarea><input type="submit" value="submit" />
</form>
- drop down box-->
<form action="/cgi-bin/dropdown.py" method="post" target="_blank">
<select name="dropdown">
<option value="Maths" selected>Maths</option>
<option value="Physics">Physics</option>
</select>
<input type="submit" value="Submit"/>
</form>
- CGI
#!/usr/bin/python
# Import modules for CGI handling
import cgi, cgitb
# Create instance of FieldStorage
form = cgi.FieldStorage()
# Get data from fields
if form.getvalue('dropdown'):
subject = form.getvalue('dropdown')
else:
subject = "Not entered"
print "Content-type:text/html\r\n\r\n"
print "<html>"
print "<head>"
print "<title>Dropdown Box - Sixth CGI Program</title>"
print "</head>"
print "<body>"
print "<h2> Selected Subject is %s</h2>" % subject
print "</body>"
print "</html>"
- cookies
- file upload
- file download
HTTP server -- programs (CGI scripts) -- interface (user input submitted through HTML<form>or<isindex>element) --> generate web content
python -m CGIHTTPSever
structure of CGI
- web server, processes requests via HTTP (Hypertext Transfer Protocol)
- process user input submitted through an HTML <FORM> or <ISINDEX> element
- cgi_directories [' /cgi-bin', ' /htbin'] containing CGI scripts (server's special cgi-bin directory)
- output - CGI script consists of two sections, separated by a blank line.
print "Content-Type: text/html" # header, telling what kind of data is following (HTML is following) print # blank line, end of headers print "<TITLE>CGI script output</TITLE>" print "Hello Morld" #html, nice formatting
using cgi module
import cgitb cgitb.enable() # display detailed reports in web browser cgitb.enable(display=0, logdir="/path/to/logdir") #have the reports saved to files
= to get at submitted form data
FieldStorage class --> can be indexed like a Python dictionary (in operator; support the standard dictionary method keys(), and built-in function len())
form = cgi.FieldStorage()
the following code checks that the fields are set to a non-empty string
if "***" not in form or "###" not in form:
print "Error"
print "please fill in *** and ### fields"
return
print "<p>***:", form["***"].value
print "<p>###:", form["###"].value
if the submitted form data contains more than one field with the same name -->form[key] is not a FieldStorage or MiniFieldStorage instance but a list of such instances; form.getvalue(key) return a list of strings; getlist()method, always returns a list of values
value = form.getlist("username")
usernames = ",".join(value)
If a field represents an uploaded file ????
fileitem = form["userfile"]
The appropriate way to read form data values was to always use the code which checks whether the obtained value is a single value or a list of values.
compact code:
import cgi
form = cgi.FieldStorage()
user = form.getfirst("user", "").upper() # This way it's safe.
for item in form.getlist("item"):
do_something(item)