Encoding with requests in python

Question

Came across a strange issue.

I am passing a dictionary as part of a POST request to a cgi script:

self.settings = {
    'SubmitCommands': ['C:\Python27\python.exe path\my_script.py']
}

Here is my code:

    settings = self.settings

    # Make web call to CGI script
    user_agent = r'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
    headers = {'User-Agent' : user_agent, "Accept": "text/plain"}
    response = requests.post(
            "path\CGI\cgi_script.py", 
            headers=headers, data=settings)

And here is the resulting traceback:

Traceback (most recent call last):
  File "path\CGI\cgi_script.py", line 119, in initi
alizeJob
    self.submitCommands = eval(inputSubmitCommands)
  File "<string>", line 1
    C:\Python27\python.exe path\my_script.py
     ^
SyntaxError: invalid syntax

However, if I do this the old fashioned way I do not get the traceback:

    settings = self.settings

    # Set and encode parameters
    params = urllib.urlencode(settings)

    # Make web call to CGI script
    user_agent = r'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
    headers = {'User-Agent' : user_agent,
                "Content-type": "application/x-www-form-urlencoded",
                "Accept": "text/plain"}
    conn = httplib.HTTPConnection(self.host)
    conn.request("POST", "path/CGI/cgi_script.py", params, headers)
    response = conn.getresponse()

Earlier today someone warned me on Stack Overflow for picking a library just because it is new. Looks like I should have listened to them. However, I am still curious about what went wrong.

Answer 1

Python is interpreting your backslashes as escape codes. Just double them up to fix that.

self.settings = {
    'SubmitCommands': ['C:\\Python27\\python.exe path\\my_script.py']
}