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whois1230

Nov-16-2020, 07:40 PM
Hello. I am learning Python 3 from a .pdf from Tutorialspoint. I am at a stage where I'm learning how to write CGI programs. I copied the following program, which when run should result in 
Hello ZARA ALI
Simple URL Example – Get Method
Here is a simple URL, which passes two values to hello_get.py program using GET method.
/cgi-bin/hello_get.py?first_name=Malhar&last_name=Lathkar
Given below is the hello_get.py script to handle the input given by web browser. We are
going to use the cgi module, which makes it very easy to access the passed information -
#!/usr/bin/python3
# Import modules for CGI handling
import cgi, cgitb
# Create instance of FieldStorage
form = cgi.FieldStorage()
# Get data from fields
first_name = form.getvalue('first_name')
last_name = form.getvalue('last_name')
print ("Content-type:text/html")
print()
print ("<html>)"
print ("<head>")
print ("<title>Hello - Second CGI Program</title>")
print ("</head>")
print ("<body>")
print ("<h2>Hello %s %s</h2>" % (first_name, last_name))
print ("</body>")
print ("</html>">)
I modified the code, as it said "invalid syntax":

#!/usr/bin/python3
# Import modules for CGI handling
import cgi, cgitb
# Create instance of FieldStorage
form = cgi.FieldStorage()
# Get data from fields
first_name = form.getvalue('first_name')
last_name = form.getvalue('last_name')
print ("Content-type:text/html")
print()
print ("<html>")
print ("<head>")
print ("<title>Hello - Second CGI Program</title>")
print ("</head>")
print ("<body>")
print ("<h2>Hello %s %s</h2>" % (first_name, last_name))
print ("</body>")
print ("</html>")
And the result I'm getting now is:
Content-type:text/html

<html>
<head>
<title>Hello - Second CGI Program</title>
</head>
<body>
<h2>Hello None None</h2>
</body>
</html>

ndc85430

Nov-16-2020, 07:53 PM
Why use the cgi module instead of a (small) web framework like Flask, or Bottle?

whois1230

Nov-18-2020, 06:35 PM
I am running the newest version of Python on Linux Ubuntu 18.04 LTS. The IDE I'm using to write Python code is IDLE. I tried to install Flask, and this is what happened:
user@Lenovo-ideapad-110-17IKB:~$ pip install Flask

Command 'pip' not found, but can be installed with:

sudo apt install python-pip

user@Lenovo-ideapad-110-17IKB:~$ sudo apt install python-pip
[sudo] password for user: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-hwe-5.4-headers-5.4.0-42 linux-hwe-5.4-headers-5.4.0-45
  linux-hwe-5.4-headers-5.4.0-47 linux-hwe-5.4-headers-5.4.0-48
  linux-hwe-5.4-headers-5.4.0-51
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  libpython-all-dev libpython-dev libpython2.7-dev python-all python-all-dev
  python-asn1crypto python-cffi-backend python-crypto python-cryptography
  python-dbus python-dev python-enum34 python-idna python-ipaddress
  python-keyring python-keyrings.alt python-pip-whl python-pkg-resources
  python-secretstorage python-setuptools python-wheel python-xdg python2.7-dev
Suggested packages:
  python-crypto-doc python-cryptography-doc python-cryptography-vectors
  python-dbus-dbg python-dbus-doc python-enum34-doc gir1.2-gnomekeyring-1.0
  python-fs python-gdata python-keyczar python-secretstorage-doc
  python-setuptools-doc
The following NEW packages will be installed:
  libpython-all-dev libpython-dev libpython2.7-dev python-all python-all-dev
  python-asn1crypto python-cffi-backend python-crypto python-cryptography
  python-dbus python-dev python-enum34 python-idna python-ipaddress
  python-keyring python-keyrings.alt python-pip python-pip-whl
  python-pkg-resources python-secretstorage python-setuptools python-wheel
  python-xdg python2.7-dev
0 upgraded, 24 newly installed, 0 to remove and 5 not upgraded.
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Get:19 http://de.archive.ubuntu.com/ubuntu bionic-updates/universe amd64 python-pip-whl all 9.0.1-2.3~ubuntu1.18.04.4 [1.653 kB]
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Get:23 http://de.archive.ubuntu.com/ubuntu bionic/universe amd64 python-wheel all 0.30.0-0.2 [36,4 kB]
Get:24 http://de.archive.ubuntu.com/ubuntu bionic/universe amd64 python-xdg all 0.25-4ubuntu1 [31,3 kB]
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user@Lenovo-ideapad-110-17IKB:~$ pip install Flask
Collecting Flask
  Downloading https://files.pythonhosted.org/packages/f2/28/2a03252dfb9ebf377f40fba6a7841b47083260bf8bd8e737b0c6952df83f/Flask-1.1.2-py2.py3-none-any.whl (94kB)
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Collecting click>=5.1 (from Flask)
  Downloading https://files.pythonhosted.org/packages/d2/3d/fa76db83bf75c4f8d338c2fd15c8d33fdd7ad23a9b5e57eb6c5de26b430e/click-7.1.2-py2.py3-none-any.whl (82kB)
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Collecting Werkzeug>=0.15 (from Flask)
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Collecting itsdangerous>=0.24 (from Flask)
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user@Lenovo-ideapad-110-17IKB:~$ pip install -U https://github.com/pallets/flask/archive/master.tar.gz
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    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-Q9wHDr-build/setup.py", line 5, in <module>
        with open("src/flask/__init__.py", encoding="utf8") as f:
    TypeError: 'encoding' is an invalid keyword argument for this function
    
    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-Q9wHDr-build/
user@Lenovo-ideapad-110-17IKB:~$

snippsat

Nov-18-2020, 07:02 PM
(Nov-18-2020, 06:35 PM)whois1230 Wrote: [ -> ]Linux Ubuntu 18.04
On 18.04 pip and python point to Python 2.7
So use pip3 and python3.
sudo apt install python3-pip
Default Python3 version on 18 is Python 3.5(old now).
If you have installed a newer Python version yourself,you my need to alias to that version.
Look also at pyenv Simple Python Version Management.
Python Wrote:CGI is going to be deprecated in Python 3.8 and removed in 3.10
A little history about WSGI(Why is WSGI necessary?) that has taken over written bye Python community that knew that CGI had no future,so new way was needed.
The modern and much better way to do similar stuff to CGI in Python,is to use eg Flask.

whois1230

Nov-19-2020, 06:10 PM
Ok, so I installed flask. And then I wrote this in IDLE:
#!/usr/bin/python3
# Import modules for CGI handling
import cgi, cgitb

# Create instance of FieldStorage
form = cgi.FieldStorage()

# Get data from fields
first_name = form.getvalue('first_name')
last_name = form.getvalue('last_name')

print ("Content-type:text/html")
print ()
print ("<html>")
print ("<head>")
print ("<title>Hello - Second CGI Program</title>")
print ("<head>")
print ("<body>")
print ("h2>Hello %s %s</h2>" % (first_name, last_name))
print ("<body>")
print ("</html")
This is the supposed output:
https://ibb.co/J2P7qkT
This is the actual output:
https://ibb.co/gW6rbqp

ndc85430

Nov-19-2020, 06:44 PM
You might have installed Flask, but you don't appear to be using it. Did you post the wrong code?

whois1230

Nov-19-2020, 07:17 PM
How can I use it?

snippsat

Nov-19-2020, 07:57 PM
(Nov-19-2020, 07:17 PM)whois1230 Wrote: [ -> ]How can I use it?
There are lot of tutorials about Flask if you search.
Here a post with some basic setup.
Python Forum > Python Coding > General Coding Help > Simple URL Example – Get Method