🌐 Mailman 3 August 2004 - Python-list - python.org

Re: how do i do this - stream file
by Christopher T King Aug. 3, 2004

Aug. 3, 2004

On Tue, 3 Aug 2004, Ajay wrote: > I have the script to do the signing and pickle the signature into a file, > but how do i allow the user to download it? Instead of pickling it to a file, pickle it to a string (using dumps). Then you can change your script to a CGI script like the following: #!/usr/local/bin/python <-- replace this with the real location of Python on your server import sys from pickle import dumps <do stuff> mydata = dumps(<something>) sys.stdout.write('Content-type: application/x-pickle\n\n') sys.stdout.write(mydata) That first sys.stdout.write is all that's needed to make a basic CGI script: the Content-type line tells the web browser what type of information to expect (the MIME type). Then you can just send whatever data you like (this works with print statements too; but remember that they append a \n to your data). For normal web pages, the MIME type is text/html. The type application/x-pickle is just something I made up, since there is no MIME type corresponding to pickled data. You may even consider just sending the signature as text and use the standard MIME type text/plain. You should put your script in the cgi-bin/ directory on your web server, and set its executable bit if it's a Unix server.

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Re: PyGTK overload
by P＠draigBrady.com Aug. 3, 2004

Aug. 3, 2004

Egbert Bouwman wrote: > Glade is for later, when I am more comfortable with PyGTK. > Or am I too conservative ? Unless you need to construct the interface at run time (for e.g. creating arrays of buttons), just let libglade create the interface for you. You gain nothing by doing this drudgery yourself. Pádraig.

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Re: Reasoning behind nested scope
by Larry Bates Aug. 3, 2004

Aug. 3, 2004

Ever since my first Fortran class some 30+ years ago I've always liked nested scopes. If you want something to be global, say so in your code. In Fortran we used common blocks, in Python you use a global directive. Making everything global can lead to many name clashes or you must have lots of unique variable names which lengthens code and makes reuse more difficult. Judicious use of OOP and globals seems to be the best approach. The more I learn/use OOP the less I seem to require globals, but there are some times they seem a preferable solution. I don't believe there is any way to call nested functions from outside their parent. If you need something like that, make the function a class and make the nested function a method of the class. HTH, Larry Bates Syscon, Inc. "Andy Baker" <andy(a)andybak.net> wrote in message news:mailman.1087.1091532385.5135.python-list@python.org... > Hi there, > > I'm learning Python at the moment and trying to grok the thinking behind > it's scoping and nesting rules. > > I was googling for nested functions and found this Guido quote: > (http://www.python.org/search/hypermail/python-1993/0343.html) > > "This is because nested function definitions don't have access to the > local variables of the surrounding block -- only to the globals of the > containing module. This is done so that lookup of globals doesn't > have to walk a chain of dictionaries -- as in C, there are just two > nested scopes: locals and globals (and beyond this, built-ins). > Therefore, nested functions have only a limited use. This was a > deliberate decision, based upon experience with languages allowing > arbitraries nesting such as Pascal and both Algols -- code with too > many nested scopes is about as readable as code with too many GOTOs. > And, of course, in Python, the "proper" way is to use an > object-oriented programming style" > > This sounds reasonable to me although nested scope always struck me as more > natural and intuitive ('Don't be surprising') > > I was wondering how the balance changed in favour of nested scope? What > changed people's minds about 'readability' vs other factors? Are nested > scopes still regarded as leading to spagetti code etc? > > (On a side note is there any way to call a nested function from outside the > parent? I was kind of expecting nested functions to be addressable through > dot notation like methods are but I can see why that wouldn't be quite > right. This might be a better question for the tutor list...) > > Andy Baker >

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Re: Call for Grant Proposals
by Peter Hansen Aug. 3, 2004

Aug. 3, 2004

Maurice Ling wrote: > Then it will means that some projects may not be able to apply for this > grant if it is the requirement of the project to be proprietary due to > business strategy. What you are saying is that all projects should be > open sourced but that may not be the case. Either that or you are > indiscriminately lobbying for the cause of open source irregards of > whether companies are ready for it or not, and then discriminating > against companies who are not ready for it yet. Although I support open > source development and had personally donated my work to Sourceforge and > Biopython project, I will think that it is tyrannic to assume all work > must be open sourced. "Tyrannic" is hardly an appropriate adjective to apply to this situation, either in letter or spirit. You are asking for money to be *given* to you here... it's a privilege, not a right. Anyway, I suspect I'm not alone (as one of the people who have made a donation, however small) in feeling very uncomfortable with the idea of much of that money being used to fund closed-source projects. -Peter

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Python and Glade-2
by P. Jouin Aug. 3, 2004

Aug. 3, 2004

I work with Linux Mandrake10 and KDE. I have compiled and install : Python 2.3.4 pygtk-2.2.0 Glade2 2.6.0 My problem is : I want to know what can i do for having Python in the Language of general option for generate my project . I have only C, C++ and Ada95 ??? Thanks (and sorry for my english)

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Re: Reasoning behind nested scope
by mwilson＠the-wire.com Aug. 3, 2004

Aug. 3, 2004

In article <mailman.1087.1091532385.5135.python-list(a)python.org>, "Andy Baker" <andy(a)andybak.net> wrote: >"This is because nested function definitions don't have access to the >local variables of the surrounding block -- only to the globals of the >containing module. This is done so that lookup of globals doesn't >have to walk a chain of dictionaries -- as in C, there are just two >nested scopes: locals and globals (and beyond this, built-ins). >Therefore, nested functions have only a limited use. This was a >deliberate decision, based upon experience with languages allowing >arbitraries nesting such as Pascal and both Algols -- code with too >many nested scopes is about as readable as code with too many GOTOs. >And, of course, in Python, the "proper" way is to use an >object-oriented programming style" > >This sounds reasonable to me although nested scope always struck me as more >natural and intuitive ('Don't be surprising') > >I was wondering how the balance changed in favour of nested scope? What >changed people's minds about 'readability' vs other factors? Are nested >scopes still regarded as leading to spagetti code etc? I guess a consensus built up that the power/safety tradeoff had given too much emphasis to safety. My own poster child for nested scopes is in some old post on c.l.p . I wanted to build a lot of similar labelled text controls in wxPython, following a naming convention. I could have written a function, but pre-nested-scope, any change I made to the information used in building the controls would have meant changing the function parameter list, and all the function calls. I came up with a template string which got parameter substituted via the '%' operator, and then `exec`ed so as code it had full access to all the info that was in the contemporary scope. Post nested scope, any info the function needed from the surrounding scope could simply be read from there. The code was much less unusual. I believe (without proof) that any language that won't let me shoot myself in the foot will also prevent me doing anything useful. Debate is heating up now about write access to enclosing scopes. We'll see how strong my faith really is. People will be able to write function nests instead of classes. >(On a side note is there any way to call a nested function from outside the >parent? I was kind of expecting nested functions to be addressable through >dot notation like methods are but I can see why that wouldn't be quite >right. This might be a better question for the tutor list...) Yup. def f1 (a): if a: x = 2 else: x = 3 def f2 (y): return y % x return f2 import os b = f1 (os.name.startswith ('p')) for c in range (10): print b (c) Regards. Mel.

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problem with unicode?
by tvlgiao(tm) Aug. 3, 2004

Aug. 3, 2004

Hi, I have a problem with unicode. In the Python Shell (Python GUI), i wrote a line: >>> print u"trịnh vũ long giao" i want to print an unicode string, but the interpreter printed an error: Unsupported characters in input does the interpreter not understand unicode chars? my program has some unicode strings, i can not save it with Python GUI IDE. does my python have problem? i use Python 2.3. can anybody help me? thanks tvlgiao --------------------------------- Do you Yahoo!? New and Improved Yahoo! Mail - 100MB free storage!

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Solved: pyUNO Converter
by Thomas Guettler Aug. 3, 2004

Aug. 3, 2004

Hi! This script will convert files to PDF with OpenOffice. Other formats (html, doc ...) should be possible, too. Have a nice day, thomas # OpenOffice1.1 comes with its own python interpreter. # This Script needs to be run with the python from OpenOffice.org: # /opt/OpenOffice.org/program/python # Start the Office before connecting: # soffice "-accept=socket,host=localhost,port=2002;urp;" # # pyUNO Imports import uno from com.sun.star.beans import PropertyValue # Python Imports import os import sys # For a list of possible export formats see # http://www.openoffice.org/files/documents/25/111/filter_description.html # or # /opt/OpenOffice.org/share/registry/data/org/openoffice/Office/TypeDetection.xcu export_format="writer_pdf_Export" export_extension="pdf" def usage(): print """Usage: %s in_dir out_dir All files in in_dir will be opened with OpenOffice.org and saved to out_dir You must start the office with this line before starting this script: soffice "-accept=socket,host=localhost,port=2002;urp;" """ % (os.path.basename(sys.argv[0])) def do_file(file, desktop, out_url): # Load File file=os.path.abspath(file) url="file:///%s" % file properties=[] p=PropertyValue() p.Name="Hidden" p.Value=True properties.append(p) doc=desktop.loadComponentFromURL( url, "_blank", 0, tuple(properties)); if not doc: print "Failed to open '%s'" % file return # Save File properties=[] p=PropertyValue() p.Name="Overwrite" p.Value=True properties.append(p) p=PropertyValue() p.Name="FilterName" p.Value=export_format properties.append(p) p=PropertyValue() p.Name="Hidden" p.Value=True basename=os.path.basename(file) idx=basename.rfind(".") assert(idx!=-1) basename=basename[:idx] url_save="%s/%s.%s" % (out_url, basename, export_extension) try: doc.storeToURL( url_save, tuple(properties)) except: print "Failed while writing: '%s'" % file doc.dispose() def main(): if len(sys.argv)!=3: usage() sys.exit(1) in_dir=sys.argv[1] out_dir=sys.argv[2] out_url="file://%s" % os.path.abspath(out_dir) print out_url # Init: Connect to running soffice process context = uno.getComponentContext() resolver=context.ServiceManager.createInstanceWithContext( "com.sun.star.bridge.UnoUrlResolver", context) try: ctx = resolver.resolve( "uno:socket,host=localhost,port=2002;urp;StarOffice.ComponentContext") except: print "Could not connect to running openoffice." usage() sys.exit() smgr=ctx.ServiceManager desktop = smgr.createInstanceWithContext("com.sun.star.frame.Desktop",ctx) files=os.listdir(in_dir) files.sort() for file in files: print "Processing %s" % file file=os.path.join(in_dir, file) do_file(file, desktop, out_url) if __name__=="__main__": main()

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Re: how do i do this - stream file
by Diez B. Roggisch Aug. 3, 2004

Aug. 3, 2004

> How do i create and stream a file? > On a webpage i have a link to a file. Next to it i would like link, which, > when pressed, runs a script that calculates the signature of the file, > pickles the signature to a file and then gives a dialog box asking the > user whether they would like to save the file or open it. > > I have the script to do the signing and pickle the signature into a file, > but how do i allow the user to download it? You'll need a webserver - there exist simple http-servers in the standard modules, you can use twisted or one of the plethorea of web-serving-solutions that exist for python, like (on particular order nor a complete list) quixote, zope, mod_python and so on.... -- Regards, Diez B. Roggisch

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socket.sendall(), non-blocking sockets, and multi-threaded socket sending
by tblack＠biamp.com Aug. 3, 2004

Aug. 3, 2004

My application requires sending a large piece (~2MB) of data to several devices on a network via TCP sockets. I have experimented with different methods for doing this and this has raised some questions about the implementation of Python sockets. (both methods use blocking sockets) Method 1: Calls socket.sendall(data) for each device in sequence, all in a single thread. Method 2: Each socket has its own thread that calls socket.send(datachunk) iteratively until all data is sent. So Method 1 sends all data to device1, then send all data to device2, etc... until all data is sent to all devices. Method 2 sends chunks of data to all devices in parallel. What I am seeing is that Method 1 is faster than Method 2. Given that the bottleneck is the actual sending of data on the sockets and not some latency in processing the message at the other end, this result makes sense to me. Method 2 involves sending the data in smaller chunks, whereas with Method 1 the chunksize is selected by the TCP/IP stack implementation, which is probably more efficient. Also, Method 2 entails context switching between the send threads. It turns out that using Method 1, all sendall() calls return immediately. I am assuming at this point that my app is in the hands of the TCP/IP stack implementation on my machine (win32-XP). Can anyone explain what happens inside sendall() for Win32? Also, I would like to get advice and opinions on what is the most efficient way to broadcast data to several devices on a network. Thanks, T

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