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  • Increasing speed of python code

    - by Curious2learn
    Hi, I have some python code that has many classes. I used cProfile to find that the total time to run the program is 68 seconds. I found that the following function in a class called Buyers takes about 60 seconds of those 68 seconds. I have to run the program about 100 times, so any increase in speed will help. Can you suggest ways to increase the speed by modifying the code? If you need more information that will help, please let me know. def qtyDemanded(self, timePd, priceVector): '''Returns quantity demanded in period timePd. In addition, also updates the list of customers and non-customers. Inputs: timePd and priceVector Output: count of people for whom priceVector[-1] < utility ''' ## Initialize count of customers to zero ## Set self.customers and self.nonCustomers to empty lists price = priceVector[-1] count = 0 self.customers = [] self.nonCustomers = [] for person in self.people: if person.utility >= price: person.customer = 1 self.customers.append(person) else: person.customer = 0 self.nonCustomers.append(person) return len(self.customers) self.people is a list of person objects. Each person has customer and utility as its attributes. EDIT - responsed added ------------------------------------- Thanks so much for the suggestions. Here is the response to some questions and suggestions people have kindly made. I have not tried them all, but will try others and write back later. (1) @amber - the function is accessed 80,000 times. (2) @gnibbler and others - self.people is a list of Person objects in memory. Not connected to a database. (3) @Hugh Bothwell cumtime taken by the original function - 60.8 s (accessed 80000 times) cumtime taken by the new function with local function aliases as suggested - 56.4 s (accessed 80000 times) (4) @rotoglup and @Martin Thomas I have not tried your solutions yet. I need to check the rest of the code to see the places where I use self.customers before I can make the change of not appending the customers to self.customers list. But I will try this and write back. (5) @TryPyPy - thanks for your kind offer to check the code. Let me first read a little on the suggestions you have made to see if those will be feasible to use. EDIT 2 Some suggested that since I am flagging the customers and noncustomers in the self.people, I should try without creating separate lists of self.customers and self.noncustomers using append. Instead, I should loop over the self.people to find the number of customers. I tried the following code and timed both functions below f_w_append and f_wo_append. I did find that the latter takes less time, but it is still 96% of the time taken by the former. That is, it is a very small increase in the speed. @TryPyPy - The following piece of code is complete enough to check the bottleneck function, in case your offer is still there to check it with other compilers. Thanks again to everyone who replied. import numpy class person(object): def __init__(self, util): self.utility = util self.customer = 0 class population(object): def __init__(self, numpeople): self.people = [] self.cus = [] self.noncus = [] numpy.random.seed(1) utils = numpy.random.uniform(0, 300, numpeople) for u in utils: per = person(u) self.people.append(per) popn = population(300) def f_w_append(): '''Function with append''' P = 75 cus = [] noncus = [] for per in popn.people: if per.utility >= P: per.customer = 1 cus.append(per) else: per.customer = 0 noncus.append(per) return len(cus) def f_wo_append(): '''Function without append''' P = 75 for per in popn.people: if per.utility >= P: per.customer = 1 else: per.customer = 0 numcustomers = 0 for per in popn.people: if per.customer == 1: numcustomers += 1 return numcustomers

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  • Python script is exiting with no output and I have no idea why

    - by Adam Tuttle
    I'm attempting to debug a Subversion post-commit hook that calls some python scripts. What I've been able to determine so far is that when I run post-commit.bat manually (I've created a wrapper for it to make it easier) everything succeeds, but when SVN runs it one particular step doesn't work. We're using CollabNet SVNServe, which I know from the documentation removes all environment variables. This had caused some problems earlier, but shouldn't be an issue now. Before Subversion calls a hook script, it removes all variables - including $PATH on Unix, and %PATH% on Windows - from the environment. Therefore, your script can only run another program if you spell out that program's absolute name. The relevant portion of post-commit.bat is: echo -------------------------- >> c:\svn-repos\company\hooks\svn2ftp.out.log set SITENAME=staging set SVNPATH=branches/staging/wwwroot/ "C:\Python3\python.exe" C:\svn-repos\company\hooks\svn2ftp.py ^ --svnUser="svnusername" ^ --svnPass="svnpassword" ^ --ftp-user=ftpuser ^ --ftp-password=ftppassword ^ --ftp-remote-dir=/ ^ --access-url=svn://10.0.100.6/company ^ --status-file="C:\svn-repos\company\hooks\svn2ftp-%SITENAME%.dat" ^ --project-directory=%SVNPATH% "staging.company.com" %1 %2 >> c:\svn-repos\company\hooks\svn2ftp.out.log echo -------------------------- >> c:\svn-repos\company\hooks\svn2ftp.out.log When I run post-commit.bat manually, for example: post-commit c:\svn-repos\company 12345, I see output like the following in svn2ftp.out.log: -------------------------- args1: c:\svn-repos\company args0: staging.company.com abspath: c:\svn-repos\company project_dir: branches/staging/wwwroot/ local_repos_path: c:\svn-repos\company getting youngest revision... done, up-to-date -------------------------- However, when I commit something to the repo and it runs automatically, the output is: -------------------------- -------------------------- svn2ftp.py is a bit long, so I apologize but here goes. I'll have some notes/disclaimers about its contents below it. #!/usr/bin/env python """Usage: svn2ftp.py [OPTION...] FTP-HOST REPOS-PATH Upload to FTP-HOST changes committed to the Subversion repository at REPOS-PATH. Uses svn diff --summarize to only propagate the changed files Options: -?, --help Show this help message. -u, --ftp-user=USER The username for the FTP server. Default: 'anonymous' -p, --ftp-password=P The password for the FTP server. Default: '@' -P, --ftp-port=X Port number for the FTP server. Default: 21 -r, --ftp-remote-dir=DIR The remote directory that is expected to resemble the repository project directory -a, --access-url=URL This is the URL that should be used when trying to SVN export files so that they can be uploaded to the FTP server -s, --status-file=PATH Required. This script needs to store the last successful revision that was transferred to the server. PATH is the location of this file. -d, --project-directory=DIR If the project you are interested in sending to the FTP server is not under the root of the repository (/), set this parameter. Example: -d 'project1/trunk/' This should NOT start with a '/'. 2008.5.2 CKS Fixed possible Windows-related bug with tempfile, where the script didn't have permission to write to the tempfile. Replaced this with a open()-created file created in the CWD. 2008.5.13 CKS Added error logging. Added exception for file-not-found errors when deleting files. 2008.5.14 CKS Change file open to 'rb' mode, to prevent Python's universal newline support from stripping CR characters, causing later comparisons between FTP and SVN to report changes. """ try: import sys, os import logging logging.basicConfig( level=logging.DEBUG, format='%(asctime)s %(levelname)s %(message)s', filename='svn2ftp.debug.log', filemode='a' ) console = logging.StreamHandler() console.setLevel(logging.ERROR) logging.getLogger('').addHandler(console) import getopt, tempfile, smtplib, traceback, subprocess from io import StringIO import pysvn import ftplib import inspect except Exception as e: logging.error(e) #capture the location of the error frame = inspect.currentframe() stack_trace = traceback.format_stack(frame) logging.debug(stack_trace) print(stack_trace) #end capture sys.exit(1) #defaults host = "" user = "anonymous" password = "@" port = 21 repo_path = "" local_repos_path = "" status_file = "" project_directory = "" remote_base_directory = "" toAddrs = "[email protected]" youngest_revision = "" def email(toAddrs, message, subject, fromAddr='[email protected]'): headers = "From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n" % (fromAddr, toAddrs, subject) message = headers + message logging.info('sending email to %s...' % toAddrs) server = smtplib.SMTP('smtp.company.com') server.set_debuglevel(1) server.sendmail(fromAddr, toAddrs, message) server.quit() logging.info('email sent') def captureErrorMessage(e): sout = StringIO() traceback.print_exc(file=sout) errorMessage = '\n'+('*'*80)+('\n%s'%e)+('\n%s\n'%sout.getvalue())+('*'*80) return errorMessage def usage_and_exit(errmsg): """Print a usage message, plus an ERRMSG (if provided), then exit. If ERRMSG is provided, the usage message is printed to stderr and the script exits with a non-zero error code. Otherwise, the usage message goes to stdout, and the script exits with a zero errorcode.""" if errmsg is None: stream = sys.stdout else: stream = sys.stderr print(__doc__, file=stream) if errmsg: print("\nError: %s" % (errmsg), file=stream) sys.exit(2) sys.exit(0) def read_args(): global host global user global password global port global repo_path global local_repos_path global status_file global project_directory global remote_base_directory global youngest_revision try: opts, args = getopt.gnu_getopt(sys.argv[1:], "?u:p:P:r:a:s:d:SU:SP:", ["help", "ftp-user=", "ftp-password=", "ftp-port=", "ftp-remote-dir=", "access-url=", "status-file=", "project-directory=", "svnUser=", "svnPass=" ]) except getopt.GetoptError as msg: usage_and_exit(msg) for opt, arg in opts: if opt in ("-?", "--help"): usage_and_exit() elif opt in ("-u", "--ftp-user"): user = arg elif opt in ("-p", "--ftp-password"): password = arg elif opt in ("-SU", "--svnUser"): svnUser = arg elif opt in ("-SP", "--svnPass"): svnPass = arg elif opt in ("-P", "--ftp-port"): try: port = int(arg) except ValueError as msg: usage_and_exit("Invalid value '%s' for --ftp-port." % (arg)) if port < 1 or port > 65535: usage_and_exit("Value for --ftp-port must be a positive integer less than 65536.") elif opt in ("-r", "--ftp-remote-dir"): remote_base_directory = arg elif opt in ("-a", "--access-url"): repo_path = arg elif opt in ("-s", "--status-file"): status_file = os.path.abspath(arg) elif opt in ("-d", "--project-directory"): project_directory = arg if len(args) != 3: print(str(args)) usage_and_exit("host and/or local_repos_path not specified (" + len(args) + ")") host = args[0] print("args1: " + args[1]) print("args0: " + args[0]) print("abspath: " + os.path.abspath(args[1])) local_repos_path = os.path.abspath(args[1]) print('project_dir:',project_directory) youngest_revision = int(args[2]) if status_file == "" : usage_and_exit("No status file specified") def main(): global host global user global password global port global repo_path global local_repos_path global status_file global project_directory global remote_base_directory global youngest_revision read_args() #repository,fs_ptr #get youngest revision print("local_repos_path: " + local_repos_path) print('getting youngest revision...') #youngest_revision = fs.youngest_rev(fs_ptr) assert youngest_revision, "Unable to lookup youngest revision." last_sent_revision = get_last_revision() if youngest_revision == last_sent_revision: # no need to continue. we should be up to date. print('done, up-to-date') return if last_sent_revision or youngest_revision < 10: # Only compare revisions if the DAT file contains a valid # revision number. Otherwise we risk waiting forever while # we parse and uploading every revision in the repo in the case # where a repository is retroactively configured to sync with ftp. pysvn_client = pysvn.Client() pysvn_client.callback_get_login = get_login rev1 = pysvn.Revision(pysvn.opt_revision_kind.number, last_sent_revision) rev2 = pysvn.Revision(pysvn.opt_revision_kind.number, youngest_revision) summary = pysvn_client.diff_summarize(repo_path, rev1, repo_path, rev2, True, False) print('summary len:',len(summary)) if len(summary) > 0 : print('connecting to %s...' % host) ftp = FTPClient(host, user, password) print('connected to %s' % host) ftp.base_path = remote_base_directory print('set remote base directory to %s' % remote_base_directory) #iterate through all the differences between revisions for change in summary : #determine whether the path of the change is relevant to the path that is being sent, and modify the path as appropriate. print('change path:',change.path) ftp_relative_path = apply_basedir(change.path) print('ftp rel path:',ftp_relative_path) #only try to sync path if the path is in our project_directory if ftp_relative_path != "" : is_file = (change.node_kind == pysvn.node_kind.file) if str(change.summarize_kind) == "delete" : print("deleting: " + ftp_relative_path) try: ftp.delete_path("/" + ftp_relative_path, is_file) except ftplib.error_perm as e: if 'cannot find the' in str(e) or 'not found' in str(e): # Log, but otherwise ignore path-not-found errors # when deleting, since it's not a disaster if the file # we want to delete is already gone. logging.error(captureErrorMessage(e)) else: raise elif str(change.summarize_kind) == "added" or str(change.summarize_kind) == "modified" : local_file = "" if is_file : local_file = svn_export_temp(pysvn_client, repo_path, rev2, change.path) print("uploading file: " + ftp_relative_path) ftp.upload_path("/" + ftp_relative_path, is_file, local_file) if is_file : os.remove(local_file) elif str(change.summarize_kind) == "normal" : print("skipping 'normal' element: " + ftp_relative_path) else : raise str("Unknown change summarize kind: " + str(change.summarize_kind) + ", path: " + ftp_relative_path) ftp.close() #write back the last revision that was synced print("writing last revision: " + str(youngest_revision)) set_last_revision(youngest_revision) # todo: undo def get_login(a,b,c,d): #arguments don't matter, we're always going to return the same thing try: return True, "svnUsername", "svnPassword", True except Exception as e: logging.error(e) #capture the location of the error frame = inspect.currentframe() stack_trace = traceback.format_stack(frame) logging.debug(stack_trace) #end capture sys.exit(1) #functions for persisting the last successfully synced revision def get_last_revision(): if os.path.isfile(status_file) : f=open(status_file, 'r') line = f.readline() f.close() try: i = int(line) except ValueError: i = 0 else: i = 0 f = open(status_file, 'w') f.write(str(i)) f.close() return i def set_last_revision(rev) : f = open(status_file, 'w') f.write(str(rev)) f.close() #augmented ftp client class that can work off a base directory class FTPClient(ftplib.FTP) : def __init__(self, host, username, password) : self.base_path = "" self.current_path = "" ftplib.FTP.__init__(self, host, username, password) def cwd(self, path) : debug_path = path if self.current_path == "" : self.current_path = self.pwd() print("pwd: " + self.current_path) if not os.path.isabs(path) : debug_path = self.base_path + "<" + path path = os.path.join(self.current_path, path) elif self.base_path != "" : debug_path = self.base_path + ">" + path.lstrip("/") path = os.path.join(self.base_path, path.lstrip("/")) path = os.path.normpath(path) #by this point the path should be absolute. if path != self.current_path : print("change from " + self.current_path + " to " + debug_path) ftplib.FTP.cwd(self, path) self.current_path = path else : print("staying put : " + self.current_path) def cd_or_create(self, path) : assert os.path.isabs(path), "absolute path expected (" + path + ")" try: self.cwd(path) except ftplib.error_perm as e: for folder in path.split('/'): if folder == "" : self.cwd("/") continue try: self.cwd(folder) except: print("mkd: (" + path + "):" + folder) self.mkd(folder) self.cwd(folder) def upload_path(self, path, is_file, local_path) : if is_file: (path, filename) = os.path.split(path) self.cd_or_create(path) # Use read-binary to avoid universal newline support from stripping CR characters. f = open(local_path, 'rb') self.storbinary("STOR " + filename, f) f.close() else: self.cd_or_create(path) def delete_path(self, path, is_file) : (path, filename) = os.path.split(path) print("trying to delete: " + path + ", " + filename) self.cwd(path) try: if is_file : self.delete(filename) else: self.delete_path_recursive(filename) except ftplib.error_perm as e: if 'The system cannot find the' in str(e) or '550 File not found' in str(e): # Log, but otherwise ignore path-not-found errors # when deleting, since it's not a disaster if the file # we want to delete is already gone. logging.error(captureErrorMessage(e)) else: raise def delete_path_recursive(self, path): if path == "/" : raise "WARNING: trying to delete '/'!" for node in self.nlst(path) : if node == path : #it's a file. delete and return self.delete(path) return if node != "." and node != ".." : self.delete_path_recursive(os.path.join(path, node)) try: self.rmd(path) except ftplib.error_perm as msg : sys.stderr.write("Error deleting directory " + os.path.join(self.current_path, path) + " : " + str(msg)) # apply the project_directory setting def apply_basedir(path) : #remove any leading stuff (in this case, "trunk/") and decide whether file should be propagated if not path.startswith(project_directory) : return "" return path.replace(project_directory, "", 1) def svn_export_temp(pysvn_client, base_path, rev, path) : # Causes access denied error. Couldn't deduce Windows-perm issue. # It's possible Python isn't garbage-collecting the open file-handle in time for pysvn to re-open it. # Regardless, just generating a simple filename seems to work. #(fd, dest_path) = tempfile.mkstemp() dest_path = tmpName = '%s.tmp' % __file__ exportPath = os.path.join(base_path, path).replace('\\','/') print('exporting %s to %s' % (exportPath, dest_path)) pysvn_client.export( exportPath, dest_path, force=False, revision=rev, native_eol=None, ignore_externals=False, recurse=True, peg_revision=rev ) return dest_path if __name__ == "__main__": logging.info('svnftp.start') try: main() logging.info('svnftp.done') except Exception as e: # capture the location of the error for debug purposes frame = inspect.currentframe() stack_trace = traceback.format_stack(frame) logging.debug(stack_trace[:-1]) print(stack_trace) # end capture error_text = '\nFATAL EXCEPTION!!!\n'+captureErrorMessage(e) subject = "ALERT: SVN2FTP Error" message = """An Error occurred while trying to FTP an SVN commit. repo_path = %(repo_path)s\n local_repos_path = %(local_repos_path)s\n project_directory = %(project_directory)s\n remote_base_directory = %(remote_base_directory)s\n error_text = %(error_text)s """ % globals() email(toAddrs, message, subject) logging.error(e) Notes/Disclaimers: I have basically no python training so I'm learning as I go and spending lots of time reading docs to figure stuff out. The body of get_login is in a try block because I was getting strange errors saying there was an unhandled exception in callback_get_login. Never figured out why, but it seems fine now. Let sleeping dogs lie, right? The username and password for get_login are currently hard-coded (but correct) just to eliminate variables and try to change as little as possible at once. (I added the svnuser and svnpass arguments to the existing argument parsing.) So that's where I am. I can't figure out why on earth it's not printing anything into svn2ftp.out.log. If you're wondering, the output for one of these failed attempts in svn2ftp.debug.log is: 2012-09-06 15:18:12,496 INFO svnftp.start 2012-09-06 15:18:12,496 INFO svnftp.done And it's no different on a successful run. So there's nothing useful being logged. I'm lost. I've gone way down the rabbit hole on this one, and don't know where to go from here. Any ideas?

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  • UITableView not reloading data on [self.tableView reloadData]

    - by donnib
    I have following code : - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NSUInteger row = [indexPath row]; static NSString *RowListCellIdentifier = @"RowListCellIdentifier"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:RowListCellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:RowListCellIdentifier]autorelease]; } NSMutableString *rowString = [[NSMutableString alloc] init]; [rowString appendString:[[[rows objectAtIndex:row] firstNumber]stringValue]]; [rowString appendString:@" : "]; [rowString appendString:[[[rows objectAtIndex:row] secondNumber]stringValue]]; [rowString appendString:@" : "]; [[cell textLabel] setText:rowString]; [rowString release]; return cell; } - (void)viewWillAppear:(BOOL)animated { [self.tableView reloadData]; [super viewWillAppear:animated]; } My problem is that the textLabel does not get reloaded with new data. If i log the rowString i see the correct value so data is good but in the UI it's the old data. I can see the cellForRowAtIndexPath beeing called so i know the reloadDatacall goes thru. What am i doing wrong ?

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  • LINQ self referencing query

    - by Chris
    I have the following SQL query: select p1.[id], p1.[useraccountid], p1.[subject], p1.[message], p1.[views], p1.[parentid], case when p2.[created] is null then p1.[created] else p2.[created] end as LastUpdate from forumposts p1 left join ( select parentid, max(created) as [created] from forumposts group by parentid ) p2 on p2.parentid = p1.id where p1.[parentid] is null order by LastUpdate desc Using the following class: public class ForumPost : PersistedObject { public int Views { get; set; } public string Message { get; set; } public string Subject { get; set; } public ForumPost Parent { get; set; } public UserAccount UserAccount { get; set; } public IList<ForumPost> Replies { get; set; } } How would I replicate such a query in LINQ? I've tried several variations, but I seem unable to get the correct join syntax. Is this simply a case of a query that is too complicated for LINQ? Can it be done using nested queries some how? The purpose of the query is to find the most recently updated posts i.e. replying to a post would bump it to the top of the list. Replies are defined by the ParentID column, which is self-referencing.

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  • How to create X509 self signed certificate for use in Apache Tomcat

    - by DaveJohnston
    I have a Java application that runs on Windows Mobile devices using a 3rd Party JVM. The application communicates with an Apache Tomcat server over HTTP. We have also used HTTPS for some connections and the certificates were created using the Sun keytool utility. First a keystore was created using genkey, then the certificate exported using export and finally that was imported into another keystore using import. The file created by genkey was loaded into the Apache server and the keystore created using import was loaded into the JVM on the PDA. Everything works as expected. I am now working with a new JVM on the PDA and (for whatever reason) I have established that this JVM requires the keystore to be in X509 (DER) format. I started working on this about a month ago and had it working, but stupidly never wrote down the steps I took, and now I can't for the life of me remember what I did. I seem to remember using openssl but other than that I am totally lost. Anything I create now using openssl and try to load into Apache causes an error at startup (Invalid Keystore Format) so I am probably missing something out entirely. Does anyone have any ideas how I should be going about creating this self-signed X509 certificate that can be loaded into Apache server and JVM running on a PDA?

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  • Querying a self referencing join with NHibernate Linq

    - by Ben
    In my application I have a Category domain object. Category has a property Parent (of type category). So in my NHibernate mapping I have: <many-to-one name="Parent" column="ParentID"/> Before I switched to NHibernate I had the ParentId property on my domain model (mapped to the corresponding database column). This made it easy to query for say all top level categories (ParentID = 0): where(c => c.ParentId == 0) However, I have since removed the ParentId property from my domain model (because of NHibernate) so I now have to do the same query (using NHibernate.Linq) like so: public IList<Category> GetCategories(int parentId) { if (parentId == 0) return _catalogRepository.Categories.Where(x => x.Parent == null).ToList(); else return _catalogRepository.Categories.Where(x => x.Parent.Id == parentId).ToList(); } The real impact that I can see, is the sql generated. Instead of a simple 'select x,y,z from categories where parentid = 0' NHibernate generates a left outer join: SELECT this_.CategoryId as CategoryId4_1_, this_.ParentID as ParentID4_1_, this_.Name as Name4_1_, this_.Slug as Slug4_1_, parent1_.CategoryId as CategoryId4_0_, parent1_.ParentID as ParentID4_0_, parent1_.Name as Name4_0_, parent1_.Slug as Slug4_0_ FROM Categories this_ left outer join Categories parent1_ on this_.ParentID = parent1_.CategoryId WHERE this_.ParentID is null Which doesn't seems much less efficient that what I had before. Is there a better way of querying these self referencing joins as it's very tempting to drop the ParentID back onto my domain model for this reason. Thanks, Ben

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  • Mapping self-table one-to-many using non-PK clolumns

    - by Harel Moshe
    Hey, i have a legacy DB to which a Person object is mapped, having a collection of family-members, like this: class Person { ... string Id; /* 9-digits string */ IList<Person> Family; ... } The PERSON table seems like: Id: CHAR(9), PK FamilyId: INT, NOT NULL and several other non-relevant columns. I'm trying to map the Family collection to the PERSON table using the FamilyId column, which is not the PK as mentioned above. So, i actually have a one-to-many which is self-table-referential. I'm getting an error saying 'Cast is not valid' when my mapping looks like this: ... <set name="Family" table="Person" lazy="false"> <key column="FamilyId" /> <one-to-many class="Person" /> </set> ... because obviously, the join NHibernate is trying to make is between the PK column, Id, and the 'secondary' column, FamilyId, instead of joining the FamilyId column to itself. Any ideas please?

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  • Self-referencing tables in Linq2Sql

    - by J-Man
    Hi, I've seen a lot of questions on self-referencing tables in Linq2Sql and how to eagerly load all child records for a particular root object. I've implemented a temporary solution by accessing all underlying properties, but you can see that this doesn't do the performance any good. The thing is though, that all records are correlated with each-other using a correlation GUID. Example below: RootElement - Id: 1 - ParentId: null - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 2 - ParentId: 1 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement2 - Id: 3 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 4 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD In my case, I do have access to the correlationId, so I can retrieve all of my records by performing the following query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' select element; But, of course, I want these elements associated with each other by executing this query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' && element.ParentId == null select element; My question is: is it possible to combine the results the first query as some sort of 'caching mechanism' for the query where I get the root element? Thanks for the input. J.

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  • Great examples of self-paced labs and exercises

    - by Mayo
    It is probably a safe bet that many of us are what they call Tactile / Kinesthetic Learners meaning that we learn best when we are physically doing something as opposed to listening to an online tutorial or reading a book. My goal with this question is to derive a list of books or online resources that serve as superb examples of self-paced programming labs and exercises. For example, I was extremely impressed with the SportsStore exercise in Steven Sanderson's Pro ASP.NET MVC Framework. The exercise spanned multiple chapters and gradually introduced new topics. I was also impressed with the materials associated with the Windows Azure Boot Camp. The demos and lab materials, accessible through the website, allow us to practice and reinforce what we can read about in articles and books. Please list any examples you might have, one per submission, below. The question is language/platform agnostic. Suggestions can be generic or specific to a given technology (PHP, SQL Server, Azure, Flash, Objective C, etc.). I only ask that the answers pertain to labs and exercises that relate to programming. My hope is that the best answers will float to the top allowing developers to review the top answers and find another programming topic that can be learned through example.

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  • self referencing object in JPA

    - by geoaxis
    Hello, I am trying to save a SystemUser entity in JPA. I also want to save certain things like who created the SystemUser and who last modified the system User as well. @ManyToOne(targetEntity = SystemUser.class) @JoinColumn private SystemUser userWhoCreated; @Temporal(TemporalType.TIMESTAMP) @DateTimeFormat(iso=ISO.DATE_TIME) private Date timeCreated; @ManyToOne(targetEntity = SystemUser.class) @JoinColumn private SystemUser userWhoLastModified; @Temporal(TemporalType.TIMESTAMP) @DateTimeFormat(iso=ISO.DATE_TIME) private Date timeLastModified; I also want to ensure that these values are not null when persisted. So If I use the NotNull JPA annotation, that is easily solved (along with reference to another entity) The problem description is simple, I cannot save rootuser without having rootuser in the system if I am to use a DataLoader class to persist JPA entity. Every other later user can be easily persisted with userWhoModified as the "systemuser" , but systemuser it's self cannot be added in this scheme. Is there a way so persist this first system user (I am thinking with SQL). This is a typical bootstrap (chicken or the egg) problem i suppose.

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  • Hibernate: deletes not cascading for self-referencing entities

    - by jwaddell
    I have the following (simplified) Hibernate entities: @Entity @Table(name = "package") public abstract class Package { protected Content content; @ManyToOne(cascade = {javax.persistence.CascadeType.ALL}) @JoinColumn(name = "content_id") @Fetch(value = FetchMode.JOIN) public Content getContent() { return content; } public void setContent(Content content) { this.content = content; } } @Entity @Table(name = "content") public class Content { private Set<Content> subContents = new HashSet<Content>(); @ManyToMany(fetch = FetchType.EAGER) @JoinTable(name = "subcontents", joinColumns = {@JoinColumn(name = "content_id")}, inverseJoinColumns = {@JoinColumn(name = "elt")}) @Cascade(value = {org.hibernate.annotations.CascadeType.DELETE, org.hibernate.annotations.CascadeType.REPLICATE}) @Fetch(value = FetchMode.SUBSELECT) public Set<Content> getSubContents() { return subContents; } public void setSubContents(Set<Content> subContents) { this.subContents = subContents; } } So a Package has a Content, and a Content is self-referencing in that it has many sub-Contents (which may contain sub-Contents of their own etc). The relationships are required to be ManyToOne (Package to Content) and ManyToMany (Content to sub-Contents) but for the case I am currently testing each sub-Content only relates to one Package or Content. The problem is that when I delete a Package and flush the session, I get a Hibernate error stating that I'm violating a foreign key constraint on table subcontents, with a particular content_id still referenced from table subcontents. I've tried specifically (recursively) deleting the Contents before deleting the Package but I get the same error. Is there a reason why this entity tree is not being deleted properly?

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  • Unobtrusive, self-hosted comments function to put onto existing web pages

    - by Pekka
    I am building a new site which will consist of a mix of dynamic and static pages. I would like to add commenting functionality to those pages with as little work as possible. I'm curious as to whether such a solution exists in PHP. The ideal set of features would be: Completely independent from the surrounding page / site: PHP code gets dropped into page, a page ID is added, done. Simple "write a comment" form Comments for each page are displayed using a PHP function Nice, clean output of <ul><li>.... that can be styled by the surrounding site Optional Captcha Optional Gravatar sensitivity Minimalistic administration area to moderate/delete comments, no ACL, can protect it using .htaccess The ideal integreation would be like this: <?php show_comments("my_page_name"); ?> this would 1. display a form to add a new comment that gets automatically associtated with my_page_name; and 2. display all comments that were made through this form using this ID. Does anybody know a solution like this? Bounty I am setting up a bounty because while there were some good suggestions, they all point to external services. I'm really curious to see whether there isn't anything self-hosted around. If this doesn't exist yet, it sure would be great to see as an Open Source project.

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  • OO model for nsxmlparser when delegate is not self

    - by richard
    Hi, I am struggling with the correct design for the delegates of nsxmlparser. In order to build my table of Foos, I need to make two types of webservice calls; one for the whole table and one for each row. It's essentially a master-query then detail-query, except the master-query-result-xml doesn't return enough information so i then need to query the detail for each row. I'm not dealing with enormous amounts of data. Anyway - previously I've just used NSXMLParser *parser = [[NSXMLParser alloc]init]; [parser setDelegate:self]; [parser parse]; and implemented all the appropriate delegate methods in whatever class i'm in. In attempt at cleanliness, I've now created two separate delegate classes and done something like: NSXMLParser *xp = [[NSXMLParser alloc]init]; MyMasterXMLParserDelegate *masterParserDelegate = [[MyMasterXMLParser]alloc]init]; [xp setDelegate:masterParserDelegate]; [xp parse]; In addition to being cleaner (in my opinion, at least), it also means each of the -parser:didStartElement implementations don't spend most of the time trying to figure out which xml they're parsing. So now the real crux of the problem. Before i split out the delegates, i had in the main class that was also implementing the delegate methods, a class-level NSMutableArray that I would just put my objects-created-from-xml in when -parser:didEndElement found the 'end' of each record. Now the delegates are in separate classes, I can't figure out how to have the -parser:didEndElement in the 'detail' delegate class "return" the created object to the calling class. At least, not in a clean OO way. I'm sure i could do it with all sorts of nasty class methods. Does the question make sense? Thanks.

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  • Entity Framework 4 Self Many-To-Many with Properties

    - by csharpnoob
    UPDATE: Solved by myself. Tricky but works. If you know a better solution, feel free to correct me. DESIGNER: CODE: Product product1 = new Product{key = "Product 1"}; sd.AddToProducts(product1); Product product2 = new Product{key = "Product 2"}; sd.AddToProducts(product2); Product product3 = new Product{key = "Product 3"}; ProductRelated pr = new ProductRelated(); pr.Products.Add(product1); pr.Products.Add(product2); product3.ProductRelateds.Add(pr); sd.AddToProducts(product3); CODE VIEW: foreach(var x in (from b in sd.Products select b)) { %><%=x.key %><br /> <% foreach (var y in x.ProductRelateds) { foreach (var k in y.Products) { %>- <%=k.key%><br /><%} } } OUTPUT Product1 Product2 Product3 - Product2 - Product1 QUESTION: Hi, i want to have a Self Reference for Releated Products on a Product Entity, something like here: http://my.safaribooksonline.com/9781430227038/modeling_a_many-to-many_comma_self-refer But i also want on the Many-To-Many Reference addional Properties like deleted, created etc. I tried to do it by another Entity "Related", but somehow it won't work. Does anyone had this Problem before? Is there any other Example? Thanks

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  • Trouble parsing self closing XML tags using SAX parser

    - by sandesh
    Hi, I am having trouble parsing self closing XML tags using SAX. I am trying to extract the link tag from the Google Base API.I am having reasonable success in parsing regular tags. Here is a snippet of the xml <entry> <id>http://www.google.com/base/feeds/snippets/15802191394735287303</id> <published>2010-04-05T11:00:00.000Z</published> <updated>2010-04-24T19:00:07.000Z</updated> <category scheme='http://base.google.com/categories/itemtypes' term='Products'/> <title type='text'>En-el1 Li-ion Battery+charger For Nikon Digital Camera</title> <link rel='alternate' type='text/html' href='http://rover.ebay.com/rover/1/711-67261-24966-0/2?ipn=psmain&amp;icep_vectorid=263602&amp;kwid=1&amp;mtid=691&amp;crlp=1_263602&amp;icep_item_id=170468125748&amp;itemid=170468125748'/> . . and so on I can parse the updates and published tags, but not the link and category tag. Here is my startElement and endElement overrides public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { if (qName.equals("title") && xmlTags.peek().equals("entry")) { insideEntryTitle = true; } xmlTags.push(qName); } public void endElement(String uri, String localName, String qName) throws SAXException { // If a "title" element is closed, we start a new line, to prepare // printing the new title. xmlTags.pop(); if (insideEntryTitle) { insideEntryTitle = false; System.out.println(); } } declaration for xmltags.. private Stack<String> xmlTags = new Stack<String>(); Any help guys? this is my first post here.. I hope I have followed posting rules! thanks a ton guys..

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  • Good ways to earn income as a self employed developer

    - by nullptr
    I was just wondering if people could share their experiences and ideas about generating / earning income from a software product or service they have personally developed. To me this seems like a good way to earn a living while doing what we love (programming) and working on projects and problems which interest us. Ie, NOT boring bank or marketing software etc 9-5 all week... Some ideas I have are things like web 2.0 style sites (Facebook,Youtube,Twitter,Digg) etc etc... - These can be very very profitable as we all know but can take years to take off. Are there ways to survive until/if this does happen? Mobile applications. Iphone, Google Android and the new up coming Nintendo DS app store. These have good potential to make it easy to find a market for your application and make selling it easy. Shareware/PC software. A bit 80's and 90's and you kind of need to be a salesman/marketer to sell it but its the only other thing I can think of. Also im not talking about doing freelance work. Im only interested in idea's you can come up with and develop your self (not other peoples ideas or problems which are you are payed to develop). Things that a sole developer or at the most 2 developers could work on and have good potential for high returns on investment (in terms of time) would be great. PS, I wish I thought of stackoverflow!

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  • Self organizing layouts

    - by user613326
    Quite a while ago i was more in websites building then i am now. In my time there where huge debates about what to use; tables or pure CSS alternatives. I went out of the webdesigning, but now an old question re-surfaces. What i would like to create is a web page design that depending on screensize, would self organize the page into columns, so that for example on a PDA it would show 1 column On an old computer monitor, it would show 2 colomns, and on a widescreen laptop it would show 3 columns. I forgot how this was called and how it was done in the past, it had to do with XML and storing data seperate from design (if i remember well), perhaps these days better methods exist to do that, does this, anyone ring this a bell ? Also i note a lot is possible with Jquery and and brouwser depending webkits. But i need to make sure that it would run on all (modern) brouwsers : Iexplorer, Firefox, chrome And Jquery is nice too, but i am kinda woried that some day one of these brouwser vendors decides that jscript like java isnt enabled by default (or is that very unlikely ?)11 Perhaps someone can point me to a method that is the prefered way to do this.

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  • Problem Implementing SSL with WSUS

    - by JohnB
    I'm working on setting up SSL on our WSUS server using a self signed certificate, but I'm running into trouble. Specifially, after running selfssl /n:CN=server.domain.local /t /v:365, and ensuring that Require Client Certificates is selected in the following directories: SimpleAuthWebService ServerSyncWebService DssAuthWebService ClientWebService APIRemoting30 I am receiving Event 120[2-5]2 upon running wsusutil.exe checkhealth. Basically, each of the directories I require the certificate on fails to work. What am I missing?

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  • How much bandwidth does my server require?

    - by Jagira
    Hello, I have blog + website hosted on Godaddy server. I get somewhere around 50k hits a day. I was thinking of hosting it on my own. I want to know whether a 2mbps connection is sufficient or not? Somebody with self-hosting experience please guide...

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  • A non interactive alternative to makecert.

    - by mark
    Dear ladies and sirs. I have a need to create a self signed certificate non interactively. Unfortunately, the only tool that I know of (makecert) is interactive - it uses GUI to ask for a password. My OS is Windows (from XP to 2008). The only thing close that I managed to find is http://www.codeproject.com/Tips/125982/How-to-run-Makecert-without-password-window.aspx, however, it is still not good. Any ideas?

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  • What would you suggest as a high school first language?

    - by ldigas
    Edit by OA: After reading some answers I'll just update the question a little. At first I put it a little bluntly, but some of those gave me some good arguments which have to be taken into consideration while making a stand on this one. (these are mostly picked up from comments and answers below). A few things to take into account: to many pupils this is a first programming language - at this stage most of them have trouble grasping a difference between data types, variable passing, ... and whatnot, less alone pointers and similar 'low level stuff' :) they will all have to pass this to get into next grade (well, big majority of them anyway) not all of them have computers at home, not all of them are willing to learn this, less alone interested in - so the concepts have to be taught on a finite time scale in school hours (as well as practice on computers) free literature is a bonus - the teacher will make some scripts and handaways, but still ... I wouldn't like to bear the parents with the burden of buying expensive literature (also, english is not a native language here ... and although they are all learning it, their ability to read it fluently is somewhat questionable) somebody gave an argument - "a language which does not get in the way of ideas" - good one accessibility on different platforms in not expecially important at this point - although most of the suggested ones are available on win as well as linux - not many macs in this part of europe (their prices are sky high for anything but specialised usage) I will check what are the licencing issues on ms express editions about using it massively in high schools for purposes like this - if someone has any info about this, please, do not be shy with it :) A friend of mine, informatics teacher - in EU it comes as something as junior cs teacher, in a local high school asked me what I thought about what should be the first language pupils should be taught? It is a technical school (a little more oriented towards mathematics than the gymnasium, but not computer oriented totally). So I'm asking you - what do you think should be the first language pupils are exposed to in highschool? They have been teaching Pascal so far, but she's not sure that's a good course. She thought about switching to C (which I resented; considering not all pupils have interests in programming, to start with, and should be taught something higher level since they are just gripping the idea of a loop and such ... for a start), I suggested python or ruby (preferably py since it handles all paradigms). What is your opinion on this one? I looked, but didn't find a similar question on SO, so if there is one, please just point me towards it. Edit: The assumption is that none of the pupils have been exposed to any programming in junior school. See also: What is the best way to teach young kids some basic programming concepts? Best ways to teach a beginner to program How and when do you teach a kid to code What is the easiest language to start with? High School Programming

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  • Simplifying const Overloading?

    - by templatetypedef
    Hello all- I've been teaching a C++ programming class for many years now and one of the trickiest things to explain to students is const overloading. I commonly use the example of a vector-like class and its operator[] function: template <typename T> class Vector { public: T& operator[] (size_t index); const T& operator[] (size_t index) const; }; I have little to no trouble explaining why it is that two versions of the operator[] function are needed, but in trying to explain how to unify the two implementations together I often find myself wasting a lot of time with language arcana. The problem is that the only good, reliable way that I know how to implement one of these functions in terms of the other is with the const_cast/static_cast trick: template <typename T> const T& Vector<T>::operator[] (size_t index) const { /* ... your implementation here ... */ } template <typename T> T& Vector<T>::operator[] (size_t index) { return const_cast<T&>(static_cast<const Vector&>(*this)[index]); } The problem with this setup is that it's extremely tricky to explain and not at all intuitively obvious. When you explain it as "cast to const, then call the const version, then strip off constness" it's a little easier to understand, but the actual syntax is frightening,. Explaining what const_cast is, why it's appropriate here, and why it's almost universally inappropriate elsewhere usually takes me five to ten minutes of lecture time, and making sense of this whole expression often requires more effort than the difference between const T* and T* const. I feel that students need to know about const-overloading and how to do it without needlessly duplicating the code in the two functions, but this trick seems a bit excessive in an introductory C++ programming course. My question is this - is there a simpler way to implement const-overloaded functions in terms of one another? Or is there a simpler way of explaining this existing trick to students? Thanks so much!

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  • Ninject WithConstructorArgument : No matching bindings are available, and the type is not self-bindable

    - by Jean-François Beauchamp
    My understanding of WithConstructorArgument is probably erroneous, because the following is not working: I have a service, lets call it MyService, whose constructor is taking multiple objects, and a string parameter called testEmail. For this string parameter, I added the following Ninject binding: string testEmail = "[email protected]"; kernel.Bind<IMyService>().To<MyService>().WithConstructorArgument("testEmail", testEmail); However, when executing the following line of code, I get an exception: var myService = kernel.Get<MyService>(); Here is the exception I get: Error activating string No matching bindings are available, and the type is not self-bindable. Activation path: 2) Injection of dependency string into parameter testEmail of constructor of type MyService 1) Request for MyService Suggestions: 1) Ensure that you have defined a binding for string. 2) If the binding was defined in a module, ensure that the module has been loaded into the kernel. 3) Ensure you have not accidentally created more than one kernel. 4) If you are using constructor arguments, ensure that the parameter name matches the constructors parameter name. 5) If you are using automatic module loading, ensure the search path and filters are correct. What am I doing wrong here? UPDATE: Here is the MyService constructor: [Ninject.Inject] public MyService(IMyRepository myRepository, IMyEventService myEventService, IUnitOfWork unitOfWork, ILoggingService log, IEmailService emailService, IConfigurationManager config, HttpContextBase httpContext, string testEmail) { this.myRepository = myRepository; this.myEventService = myEventService; this.unitOfWork = unitOfWork; this.log = log; this.emailService = emailService; this.config = config; this.httpContext = httpContext; this.testEmail = testEmail; } I have standard bindings for all the constructor parameter types. Only 'string' has no binding, and HttpContextBase has a binding that is a bit different: kernel.Bind<HttpContextBase>().ToMethod(context => new HttpContextWrapper(new HttpContext(new MyHttpRequest("", "", "", null, new StringWriter())))); and MyHttpRequest is defined as follows: public class MyHttpRequest : SimpleWorkerRequest { public string UserHostAddress; public string RawUrl; public MyHttpRequest(string appVirtualDir, string appPhysicalDir, string page, string query, TextWriter output) : base(appVirtualDir, appPhysicalDir, page, query, output) { this.UserHostAddress = "127.0.0.1"; this.RawUrl = null; } }

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  • class __init__ (not instance __init__)

    - by wallacoloo
    Here's a very simple example of what I'm trying to get around: class Test(object): some_dict = {Test: True} The problem is that I cannot refer to Test while it's still being defined Normally, I'd just do this: class Test(object): def __init__(self): self.__class__.some_dict = {Test: True} But I never create an instance of this class. It's really just a container to hold a group of related functions and data (I have several of these classes, and I pass around references to them, so it is necessary for Test to be it's own class) So my question is, how could I refer to Test while it's being defined, or is there something similar to __init__ that get's called as soon as the class is defined? If possible, I want self.some_dict = {Test: True} to remain inside the class definition. This is the only way I know how to do this so far: class Test(object): @classmethod def class_init(cls): cls.some_dict = {Test: True} Test.class_init()

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  • Django, want to upload eather image (ImageField) or file (FileField)

    - by Serg
    I have a form in my html page, that prompts user to upload File or Image to the server. I want to be able to upload ether file or image. Let's say if user choose file, image should be null, and vice verso. Right now I can only upload both of them, without error. But If I choose to upload only one of them (let's say I choose image) I will get an error: "Key 'attachment' not found in <MultiValueDict: {u'image': [<InMemoryUploadedFile: police.jpg (image/jpeg)>]}>" models.py: #Description of the file class FileDescription(models.Model): TYPE_CHOICES = ( ('homework', 'Homework'), ('class', 'Class Papers'), ('random', 'Random Papers') ) subject = models.ForeignKey('Subjects', null=True, blank=True) subject_name = models.CharField(max_length=100, unique=False) category = models.CharField(max_length=100, unique=False, blank=True, null=True) file_type = models.CharField(max_length=100, choices=TYPE_CHOICES, unique=False) file_uploaded_by = models.CharField(max_length=100, unique=False) file_name = models.CharField(max_length=100, unique=False) file_description = models.TextField(unique=False, blank=True, null=True) file_creation_time = models.DateTimeField(editable=False) file_modified_time = models.DateTimeField() attachment = models.FileField(upload_to='files', blank=True, null=True, max_length=255) image = models.ImageField(upload_to='files', blank=True, null=True, max_length=255) def __unicode__(self): return u'%s' % (self.file_name) def get_fields(self): return [(field, field.value_to_string(self)) for field in FileDescription._meta.fields] def filename(self): return os.path.basename(self.image.name) def category_update(self): category = self.file_name return category def save(self, *args, **kwargs): if self.category is None: self.category = FileDescription.category_update(self) for field in self._meta.fields: if field.name == 'image' or field.name == 'attachment': field.upload_to = 'files/%s/%s/' % (self.file_uploaded_by, self.file_type) if not self.id: self.file_creation_time = datetime.now() self.file_modified_time = datetime.now() super(FileDescription, self).save(*args, **kwargs) forms.py class ContentForm(forms.ModelForm): file_name =forms.CharField(max_length=255, widget=forms.TextInput(attrs={'size':20})) file_description = forms.CharField(widget=forms.Textarea(attrs={'rows':4, 'cols':25})) class Meta: model = FileDescription exclude = ('subject', 'subject_name', 'file_uploaded_by', 'file_creation_time', 'file_modified_time', 'vote') def clean_file_name(self): name = self.cleaned_data['file_name'] # check the length of the file name if len(name) < 2: raise forms.ValidationError('File name is too short') # check if file with same name is already exists if FileDescription.objects.filter(file_name = name).exists(): raise forms.ValidationError('File with this name already exists') else: return name views.py if request.method == "POST": if "upload-b" in request.POST: form = ContentForm(request.POST, request.FILES, instance=subject_id) if form.is_valid(): # need to add some clean functions # handle_uploaded_file(request.FILES['attachment'], # request.user.username, # request.POST['file_type']) form.save() up_f = FileDescription.objects.get_or_create( subject=subject_id, subject_name=subject_name, category = request.POST['category'], file_type=request.POST['file_type'], file_uploaded_by = username, file_name=form.cleaned_data['file_name'], file_description=request.POST['file_description'], image = request.FILES['image'], attachment = request.FILES['attachment'], ) return HttpResponseRedirect(".")

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