Web interface to a Python script, with "streaming text" - python

I have a Python command-line script that can take some time to run (from 5 seconds to 5 minutes), depending on the checks it does. The script uses many command-line arguments, some mandatory, most optional.
I'd like to "webify" this script, making it possible to access it from a Web browser, but without changing the core python script, so by launching it from something else (like another Python script for instance)
I've used mod_python with Apache before so it's not too much of a problem to build a Python script that generates a Web page with a form and a Submit button and run my core python script from it.
The problem is with the output of the core python script. I don't want to wait until it has completed to display its output in a DIV (or in a FRAME). As soon as it generates a line, I want that line to be displayed on the Web interface, a kind of text streaming in the DIV.
I know how to do this from a Javascript contained in a HTML page or as an external Javascript file, but not from the output of another program.
Any idea how I can achieve this? I prefer to keep it all Python+Apache but if something else is really required (PHP, AJAX, Javascript, ...), I can live with it.
As suggested by whatnick below, I tried to redirect the output of the core python script in a temporary file and display this file using the AJAX Logfile Trailer & Viewer code I found on the Web.
It sort of works but there is still some buffering, as the lines appear in the "log tail page" in several chunks of lines, not lines by lines. This is most probably due to the fact the AJAX script reloads the log file using a timer, every X milliseconds (configurable in the script, used for a Javascript timer). Even if I lower it, it still not fast enough for my core script, which can sometimes output several lines very fast.

You can log the output from your lengthy script to a file and use a javascript timer based code to pull, parse and display content of the log periodically. If pulling the entire log is too much, you can also delegate to a smaller/faster server side python script to parse the log and pass on the tail of the log to the calling javascript. This is how router logs etc. in embedded devices is displayed.
Good luck. Here is a small tutorial on Javascript Timers.

For IE and Firefox, if you stream your response, it will start rendering before the full page is provided. You can thus stream a log of what is going on in the middle of an HTML file. Once the process is completed, you render the rest of the page as normal.
You will have to go through some convolutions to get a normal Python template engine to work with that since they tend to do everything in one shot.
Chrome does not seem to like this very well (I expect that is a webkit thing so you can probably discount Safari from this trick as well) and I am not sure about Opera.

Related

How to make a webpage give string input to main.exe running on windows and download word document output?

Hello stack overflow world!
I'm a self-thought programing enthusiast, with not much experience.
I have made a python script and turned it into .exe that more or less does the following:
Based on user input, opens some webpages and saves them as HTML files,
Runs an excel macro that refreshes power queries connected to those saved files,
Runs a macro in a word document linked to that excel, that smooths out the text and saves output as a word document containing sales a purches agreemnent for a real estate, filled with information scraped online.
I was trying to host this whole operation to a sever, to be able to run it from anywhere. Any ideas how I might be able to do it? I ran out of ides what to type in google in order to procdeed with my little project.
I have looked up Common Gateway Interface (CGI) but I'm not sure if this is the right approach.

Dynamically read value of html input field: python

I have an external browser plugin (which is blackbox to me). This plugin tries to fill values to input fields of html page (on load. I want to make a program, which is able if the external program filled values properly.
So what I want to do is to open an url from my python program in a browser. On load of this page is automatically executed the plugin and tries to insert values. After that I want to find specific input fields and resolve, whether they are filled correctly or not in the current instance of the browser and page.
Is there any way to do such thing using python (standard or 3rd party) modules? Could you recommend me any?
(Note: I also want to build exe file using cx_freeze, so the best would be, if the module does not depend on external files)
Thanks.
I would suggest using PyQt or Selenium.

Can Not execute Python .py file using RobotFramework like Javascript

Has anyone found a method for executing their .py files from the Robot Framework like you can for JS?
RobotFramework:
Executes the given JavaScript code.
code may contain multiple statements and the return value of last
statement is returned by this keyword.
code may be divided into multiple cells in the test data. In that
case, the parts are catenated together without adding spaces.
If code is an absolute path to an existing file, the JavaScript to
execute will be read from that file. Forward slashes work as a path
separator on all operating systems. The functionality to read the code
from a file was added in SeleniumLibrary 2.5.
Note that, by default, the code will be executed in the context of the
Selenium object itself, so this will refer to the Selenium object. Use
window to refer to the window of your application, e.g.
window.document.getElementById('foo').
Example: Execute JavaScript window.my_js_function('arg1', 'arg2')
Execute JavaScript ${CURDIR}/js_to_execute.js
It's bs that I can't run my .py files this way...
The Execute Javascript extension isn't a part of RobotFramework, it's something added by the Selenium integration, it would therefore follow that you can't use Selenium to execute a .py file.
That said, RobotFramework is written in Python and can obviously be extended with a Python script.
Can you clear up what you're actually trying to achieve here though?
My concern is that if you're using a .py file in your test state to validate your code, isn't that introducing an uncertainty that means that what you're testing is not the same as the code that gets executed when you release your project?
A bit more detail would help a lot here!

Trying to automate the fpga build process in Xilinx using python scripts

I want to automate the entire process of creating ngs,bit and mcs files in xilinx and have these files be automatically be associated with certain folders in the svn repository. What I need to know is that is there a log file that gets created in the back end of the Xilinx gui which records all the commands I run e.g open project,load file,synthesize etc.
Also the other part that I have not been able to find is a log file that records the entire process of synthesis, map,place and route and generate programming file. Specially record any errors that the tool encountered during these processes.
If any of you can point me to such files if they exist it would be great. I haven't gotten much out of my search but maybe I didn't look enough.
Thanks!
Well, it is definitely a nice project idea but a good amount of work. There's always a reason why an IDE was built – a simple search yields the "Command Line Tools User Guide" for various versions of Xilinx ISE, like for 14.3, 380 pages about
Overview and list of features
Input and output files
Command line syntax and options
Report and message information
ISE is a GUI for various command line executables, most of them are located in the subfolder 14.5/ISE_DS/ISE/bin/lin/ (in this case: Linux executables for version 14.5) of your ISE installation root. You can review your current parameters for each action by right clicking the item in the process tree and selecting "Process properties".
On the Python side, consider using the subprocess module:
The subprocess module allows you to spawn new processes, connect to their input/output/error pipes, and obtain their return codes.
Is this the entry point you were looking for?
As phineas said, what you are trying to do is quite an undertaking.
I've been there done that, and there are countless challenges along the way. For example, if you want to move generated files to specific folders, how do you classify these files in order to figure out which files are which? I've created a project called X-MimeTypes that attempts to classify the files, but you then need a tool to parse the EDA mime type database and use that to determine which files are which.
However there is hope, so to answer the two main questions you've pointed out:
To be able to automatically move generated files to predetermined paths. From what you are saying it seems like you want to do this to make the versioning process easier? There is already a tool that does this for you based on "design structures" that you create and that can be shared within a team. The tool is called Scineric Workspace so check it out. It also have built in Git and SVN support which ignores things according to the design structure and in most cases it filters all generated things by vendor tools without you having to worry about it.
You are looking for a log file that shows all commands that were run. As phineas said, you can check out the Command Line Tools User guides for ISE, but be aware that the commands to run have changed again in Vivado. The log file of each process also usually states the exact command with its parameters that have been called. This should be close to the top of the report. If you look for one log file that contains everything, that does not exist. Again, Scineric Workspace supports evoking flows from major vendors (ISE, Vivado, Quartus) and it produces one log file for all processes together while still allowing each process to also create its own log file. Errors, warning etc. are also marked properly in this big report. Scineric has a tcl shell mode as well, so your python tool can run it in the background and parse the complete log file it creates.
If you have more questions on the above, I will be happy to help.
Hope this helps,
Jaco

Interact with other programs using Python

I'm having the idea of writing a program using Python which shall find a lyric of a song whose name I provided. I think the whole process should boil down to couple of things below. These are what I want the program to do when I run it:
prompt me to enter a name of a song
copy that name
open a web browser (google chrome for example)
paste that name in the address bar and find information about the song
open a page that contains the lyrics
copy that lyrics
run a text editor (like Microsoft Word for instance)
paste the lyrics
save the new text file with the name of the song
I am not asking for code, of course. I just want to know the concepts or ideas about how to use python to interact with other programs
To be more specific, I think I want to know, fox example, just how we point out where is the address bar in Google Chrome and tell python to paste the name there. Or how we tell python how to copy the lyrics as well as paste it into the Microsof Word's sheet then save it.
I've been reading (I'm still reading) several books on Python: Byte of python, Learn python the hard way, Python for dummies, Beginning Game Development with Python and Pygame. However, I found out that it seems like I only (or almost only) learn to creat programs that work on itself (I can't tell my program to do things I want with other programs that are already installed on my computer)
I know that my question somehow sounds rather silly, but I really want to know how it works, the way we tell Python to regconize that this part of the Google chrome browser is the address bar and that it should paste the name of the song in it. The whole idea of making python interact with another program is really really vague to me and I just
extremely want to grasp that.
Thank you everyone, whoever spend their time reading my so-long question.
ttriet204
If what you're really looking into is a good excuse to teach yourself how to interact with other apps, this may not be the best one. Web browsers are messy, the timing is going to be unpredictable, etc. So, you've taken on a very hard task—and one that would be very easy if you did it the usual way (talk to the server directly, create the text file directly, etc., all without touching any other programs).
But if you do want to interact with other apps, there are a variety of different approaches, and which is appropriate depends on the kinds of apps you need to deal with.
Some apps are designed to be automated from the outside. On Windows, this nearly always means they a COM interface, usually with an IDispatch interface, for which you can use pywin32's COM wrappers; on Mac, it means an AppleEvent interface, for which you use ScriptingBridge or appscript; on other platforms there is no universal standard. IE (but probably not Chrome) and Word both have such interfaces.
Some apps have a non-GUI interface—whether that's a command line you can drive with popen, or a DLL/SO/DYLIB you can load up through ctypes. Or, ideally, someone else has already written Python bindings for you.
Some apps have nothing but the GUI, and there's no way around doing GUI automation. You can do this at a low level, by crafting WM_ messages to send via pywin32 on Windows, using the accessibility APIs on Mac, etc., or at a somewhat higher level with libraries like pywinauto, or possibly at the very high level of selenium or similar tools built to automate specific apps.
So, you could do this with anything from selenium for Chrome and COM automation for Word, to crafting all the WM_ messages yourself. If this is meant to be a learning exercise, the question is which of those things you want to learn today.
Let's start with COM automation. Using pywin32, you directly access the application's own scripting interfaces, without having to take control of the GUI from the user, figure out how to navigate menus and dialog boxes, etc. This is the modern version of writing "Word macros"—the macros can be external scripts instead of inside Word, and they don't have to be written in VB, but they look pretty similar. The last part of your script would look something like this:
word = win32com.client.dispatch('Word.Application')
word.Visible = True
doc = word.Documents.Add()
doc.Selection.TypeText(my_string)
doc.SaveAs(r'C:\TestFiles\TestDoc.doc')
If you look at Microsoft Word Scripts, you can see a bunch of examples. However, you may notice they're written in VBScript. And if you look around for tutorials, they're all written for VBScript (or older VB). And the documentation for most apps is written for VBScript (or VB, .NET, or even low-level COM). And all of the tutorials I know of for using COM automation from Python, like Quick Start to Client Side COM and Python, are written for people who already know about COM automation, and just want to know how to do it from Python. The fact that Microsoft keeps changing the name of everything makes it even harder to search for—how would you guess that googling for OLE automation, ActiveX scripting, Windows Scripting House, etc. would have anything to do with learning about COM automation? So, I'm not sure what to recommend for getting started. I can promise that it's all as simple as it looks from that example above, once you do learn all the nonsense, but I don't know how to get past that initial hurdle.
Anyway, not every application is automatable. And sometimes, even if it is, describing the GUI actions (what a user would click on the screen) is simpler than thinking in terms of the app's object model. "Select the third paragraph" is hard to describe in GUI terms, but "select the whole document" is easy—just hit control-A, or go to the Edit menu and Select All. GUI automation is much harder than COM automation, because you either have to send the app the same messages that Windows itself sends to represent your user actions (e.g., see "Menu Notifications") or, worse, craft mouse messages like "go (32, 4) pixels from the top-left corner, click, mouse down 16 pixels, click again" to say "open the File menu, then click New".
Fortunately, there are tools like pywinauto that wrap up both kinds of GUI automation stuff up to make it a lot simpler. And there are tools like swapy that can help you figure out what commands you want to send. If you're not wedded to Python, there are also tools like AutoIt and Actions that are even easier than using swapy and pywinauto, at least when you're getting started. Going this way, the last part of your script might look like:
word.Activate()
word.MenuSelect('File->New')
word.KeyStrokes(my_string)
word.MenuSelect('File->Save As')
word.Dialogs[-1].FindTextField('Filename').Select()
word.KeyStrokes(r'C:\TestFiles\TestDoc.doc')
word.Dialogs[-1].FindButton('OK').Click()
Finally, even with all of these tools, web browsers are very hard to automate, because each web page has its own menus, buttons, etc. that aren't Windows controls, but HTML. Unless you want to go all the way down to the level of "move the mouse 12 pixels", it's very hard to deal with these. That's where selenium comes in—it scripts web GUIs the same way that pywinauto scripts Windows GUIs.
The following script uses Automa to do exactly what you want (tested on Word 2010):
def find_lyrics():
print 'Please minimize all other open windows, then enter the song:'
song = raw_input()
start("Google Chrome")
# Disable Google's autocompletion and set the language to English:
google_address = 'google.com/webhp?complete=0&hl=en'
write(google_address, into="Address")
press(ENTER)
write(song + ' lyrics filetype:txt')
click("I'm Feeling Lucky")
press(CTRL + 'a', CTRL + 'c')
press(ALT + F4)
start("Microsoft Word")
press(CTRL + 'v')
press(CTRL + 's')
click("Desktop")
write(song + ' lyrics', into="File name")
click("Save")
press(ALT + F4)
print("\nThe lyrics have been saved in file '%s lyrics' "
"on your desktop." % song)
To try it out for yourself, download Automa.zip from its Download page and unzip into, say, c:\Program Files. You'll get a folder called Automa 1.1.2. Run Automa.exe in that folder. Copy the code above and paste it into Automa by right-clicking into the console window. Press Enter twice to get rid of the last ... in the window and arrive back at the prompt >>>. Close all other open windows and type
>>> find_lyrics()
This performs the required steps.
Automa is a Python library: To use it as such, you have to add the line
from automa.api import *
to the top of your scripts and the file library.zip from Automa's installation directory to your environment variable PYTHONPATH.
If you have any other questions, just let me know :-)
Here's an implementation in Python of #Matteo Italia's comment:
You are approaching the problem from a "user perspective" when you
should approach it from a "programmer perspective"; you don't need to
open a browser, copy the text, open Word or whatever, you need to
perform the appropriate HTTP requests, parse the relevant HTML,
extract the text and write it to a file from inside your Python
script. All the tools to do this are available in Python (in
particular you'll need urllib2 and BeautifulSoup).
#!/usr/bin/env python
import codecs
import json
import sys
import urllib
import urllib2
import bs4 # pip install beautifulsoup4
def extract_lyrics(page):
"""Extract lyrics text from given lyrics.wikia.com html page."""
soup = bs4.BeautifulSoup(page)
result = []
for tag in soup.find('div', 'lyricbox'):
if isinstance(tag, bs4.NavigableString):
if not isinstance(tag, bs4.element.Comment):
result.append(tag)
elif tag.name == 'br':
result.append('\n')
return "".join(result)
# get artist, song to search
artist = raw_input("Enter artist:")
song = raw_input("Enter song:")
# make request
query = urllib.urlencode(dict(artist=artist, song=song, fmt="realjson"))
response = urllib2.urlopen("http://lyrics.wikia.com/api.php?" + query)
data = json.load(response)
if data['lyrics'] != 'Not found':
# print short lyrics
print(data['lyrics'])
# get full lyrics
lyrics = extract_lyrics(urllib2.urlopen(data['url']))
# save to file
filename = "[%s] [%s] lyrics.txt" % (data['artist'], data['song'])
with codecs.open(filename, 'w', encoding='utf-8') as output_file:
output_file.write(lyrics)
print("written '%s'" % filename)
else:
sys.exit('not found')
Example
$ printf "Queen\nWe are the Champions" | python get-lyrics.py
Output
I've paid my dues
Time after time
I've done my sentence
But committed no crime
And bad mistakes
I've made a few
I've had my share of sand kicked [...]
written '[Queen] [We are the Champions] lyrics.txt'
If you really want to open a browser, etc, look at selenium. But that's overkill for your purposes. Selenium is used to simulate button clicks, etc for testing the appearance of websites on various browsers, etc. Mechanize is less of an overkill for this
What you really want to do is understand how a browser (or any other program) works under the hood i.e. when you click on the mouse or type on the keyboard or hit Save, what does the program do behind the scenes? It is this behind-the-scenes work that you want your python code to do.
So, use urllib, urllib2 or requests (or heck, even scrapy) to request a web page (learn how to put together the url to a google search or the php GET request of a lyrics website). Google also has a search API that you can take advantage of, to perform a google search.
Once you have your results from your page request, parse it with xml, beautifulsoup, lxlml, etc and find the section of the request result that has the information you're after.
Now that you have your lyrics, the simplest thing to do is open a text file and dump the lyrics in there and write to disk. But if you really want to do it with MS Word, then open a doc file in notepad or notepad++ and look at its structure. Now, use python to build a document with similar structure, wherein the content will be the downloaded lyrics.
If this method fails, you could look into pywinauto or such to automate the pasting of text into an MS Word doc and clicking on Save
Citation: Matteo Italia, g.d.d.c from the comments on the OP
You should look into a package called selenium for interacting with web browsers

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