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  • Event Source Live streaming in Ruby on rails onError method

    - by kishorebjv
    I'm trying to implement basic rails4 code with eventsource API & Action controller live, Everything is fine but I'm not able to reach event listner . Controller code: class HomeController < ApplicationController include ActionController::Live def tester response.headers["Content-Type"] = "text/event-stream" 3.times do |n| response.stream.write "message: hellow world! \n\n" sleep 2 end end Js code: var evSource = new EventSource("/home/tester"); evSource.onopen = function (e) { console.log("OPEN state \n"+e.data); }; evSource.addEventListener('message',function(e){ console.log("EventListener .. code.."); },false); evSource.onerror = function (e) { console.log("Error State \n\n"+e.data); }; & When i reloading the page, My console output was "OPEN state" & then "Error State" as output.. event-listener code was not displaying . 1.When I'm curling the page, "message: Hellow world!" was displaying. 2.I changed in development.rb config.cache_classes = true config.eager_load = true 3. My browsers are chrome & firefox are latest versions, so no issues with them, Where I'm missing? suggestions please!

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  • autorelease object not confirming protocol does not give any warning

    - by Sahil Wasan
    I have a class "ABC" and its method which returns non autoreleases object of that class. @interface ABC:NSObject +(ABC *)aClassMethodReturnsObjectWhichNotAutoreleased; @end @implementation ABC +(ABC *)aClassMethodReturnsObjectWhichNotAutoreleased{ ABC *a = [[ABC alloc]init]; return a; } @end If I have a protocol Foo. @Protocol Foo @required -(void)abc; @end My ABC class is "not" confirming Foo protocols. 1st call id<Foo> obj = [ABC aClassMethodReturnsObjectWhichNotAutoreleased]; //show warning It shows warning "Non Compatible pointers.." thats good.Abc did not confirm protocol Foo BUT 2nd call id<Foo> obj = [NSArray arrayWithObjects:@"abc",@"def",nil]; // It will "not" show warning as it will return autorelease object.NSArray don't confirm protocol Foo In first call compiler gives warning and in second call compiler is not giving any warning.I think that is because i am not returning autorelease object. Why is compiler not giving warning in 2nd call as NSArray is also not confirming FOO Thanks in advance

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  • Writing functions of tuples conveniently in Scala

    - by Alexey Romanov
    Quite a few functions on Map take a function on a key-value tuple as the argument. E.g. def foreach(f: ((A, B)) ? Unit): Unit. So I looked for a short way to write an argument to foreach: > val map = Map(1 -> 2, 3 -> 4) map: scala.collection.immutable.Map[Int,Int] = Map(1 -> 2, 3 -> 4) > map.foreach((k, v) => println(k)) error: wrong number of parameters; expected = 1 map.foreach((k, v) => println(k)) ^ > map.foreach({(k, v) => println(k)}) error: wrong number of parameters; expected = 1 map.foreach({(k, v) => println(k)}) ^ > map.foreach(case (k, v) => println(k)) error: illegal start of simple expression map.foreach(case (k, v) => println(k)) ^ I can do > map.foreach(_ match {case (k, v) => println(k)}) 1 3 Any better alternatives?

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  • Analyzing an IronPython Scope

    - by Vercinegetorix
    I'm trying to write C# code with an embedded IronPython script. Then want to analyze the contents of the script, i.e. list all variables, functions, class and their members/methods. There's an easy way to start, assuming I've got a scope defined and code executed in it already: dynamic variables=pyScope.GetVariables(); foreach (string v in variables) { dynamic dynamicV=pyScope.GetVariable(); /*seems to return everything. variables, functions, classes, instances of classes*/ } But how do I figure out what the type of a variable is? For the following python 'objects', dynamicV.GetType() will return different values: x=5 --system.Int32 y="asdf" --system.String def func():... --IronPython.Runtime.PythonFunction z=class() -- IronPython.Runtime.Types.OldInstance, how can I identify what the actual python class is? class NewClass -- throws an error, GetType() is unavailable. This is almost what I'm looking for. I could capture the exception thrown when unavailable and assume it's a class declaration, but that seems unclean. Is there a better approach? To discover the members/methods of a class it looks like I can use: ObjectOperations op = pyEngine.Operations; object instance = op.Call("className"); foreach (string j in op.GetMemberNames("className")) { object member=op.GetMember(instance, j); Console.WriteLine(member.GetType()); /*once again, GetType() provides some info about the type of the member, but returns null sometimes*/ } Also, how do I get the parameters to a method? Thanks!

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  • Python: problem with tiny script to delete files

    - by Rosarch
    I have a project that used to be under SVN, but now I'm moving it to Mercurial, so I want to clear out all the .svn files. It's a little too big to do it by hand, so I decided to write a python script to do it. But it isn't working. def cleandir(dir_path): print "Cleaning %s\n" % dir_path toDelete = [] files = os.listdir(dir_path) for filedir in files: print "considering %s" % filedir # continue if filedir == '.' or filedir == '..': print "skipping %s" % filedir continue path = dir_path + os.sep + filedir if os.path.isdir(path): cleandir(path) else: print "not dir: %s" % path if 'svn' in filedir: toDelete.append(path) print "Files to be deleted:" for candidate in toDelete: print candidate print "Delete all? [y|n]" choice = raw_input() if choice == 'y': for filedir in toDelete: if os.path.isdir(filedir): os.rmdir(filedir) else: os.unlink(filedir) exit() if __name__ == "__main__": cleandir(dir) The print statements show that it's only "considering" the filedirs whose names start with ".". However, if I uncomment the continue statement, all the filedirs are "considered". Why is this? Or is there some other utility that already exists to recursively de-SVN-ify a directory tree?

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  • How to use libavformat for a separate encoder?

    - by Brendon Tsai
    I've build a encoder based on the sample of QUALCOMM, which captures the video and compresses it into h264 file. I am using Android 4.2.2. Now I want to add a mp4 muxer into this encoder(actually, just video will be fine, I don't need audio). I want to use FFMpeg. But after I read the example, I found out that the muxer was using the encoder of FFMpeg. I don't know how to use the muxer part for another encoder. I've read this post, but I don't understand how the code provide video stream to the muxer. I think that mainly because I don't understand these code: AVCodecContext * strmCodec = oFmtCtx->streams[0]->codec; // Fill the required properties for codec context. // *from the documentation: // *The user sets codec information, the muxer writes it to the output. // *Mandatory fields as specified in AVCodecContext // *documentation must be set even if this AVCodecContext is // *not actually used for encoding. my_tune_codec(strmCodec); Can anyone give me a hint? Thank you!

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  • How can I use TDD to solve a puzzle with an unknown answer?

    - by matthewsteele
    Recently I wrote a Ruby program to determine solutions to a "Scramble Squares" tile puzzle: I used TDD to implement most of it, leading to tests that looked like this: it "has top, bottom, left, right" do c = Cards.new card = c.cards[0] card.top.should == :CT card.bottom.should == :WB card.left.should == :MT card.right.should == :BT end This worked well for the lower-level "helper" methods: identifying the "sides" of a tile, determining if a tile can be validly placed in the grid, etc. But I ran into a problem when coding the actual algorithm to solve the puzzle. Since I didn't know valid possible solutions to the problem, I didn't know how to write a test first. I ended up writing a pretty ugly, untested, algorithm to solve it: def play_game working_states = [] after_1 = step_1 i = 0 after_1.each do |state_1| step_2(state_1).each do |state_2| step_3(state_2).each do |state_3| step_4(state_3).each do |state_4| step_5(state_4).each do |state_5| step_6(state_5).each do |state_6| step_7(state_6).each do |state_7| step_8(state_7).each do |state_8| step_9(state_8).each do |state_9| working_states << state_9[0] end end end end end end end end end So my question is: how do you use TDD to write a method when you don't already know the valid outputs? If you're interested, the code's on GitHub: Tests: https://github.com/mattdsteele/scramblesquares-solver/blob/master/golf-creator-spec.rb Production code: https://github.com/mattdsteele/scramblesquares-solver/blob/master/game.rb

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  • Replacing words in string

    - by abkai
    Okay, so I have the following little function: def swap(inp): inp = inp.split() out = "" for item in inp: ind = inp.index(item) item = item.replace("i am", "you are") item = item.replace("you are", "I am") item = item.replace("i'm", "you're") item = item.replace("you're", "I'm") item = item.replace("my", "your") item = item.replace("your", "my") item = item.replace("you", "I") item = item.replace("my", "your") item = item.replace("i", "you") inp[ind] = item for item in inp: ind = inp.index(item) item = item + " " inp[ind] = item return out.join(inp) Which, while it's not particularly efficient gets the job done for shorter sentences. Basically, all it does is swaps pronoun etc. perspectives. This is fine when I throw a string like "I love you" at it, it returns "you love me" but when I throw something like: you love your version of my couch because I love you, and you're a couch-lover. I get: I love your versyouon of your couch because I love I, and I'm a couch-lover. I'm confused as to why this is happening. I explicitly split the string into a list to avoid this. Why would it be able to detect it as being a part of a list item, rather than just an exact match? Also, slightly deviating to avoid having to post another question so similar; if a solution to this breaks this function, what will happen to commas, full stops, other punctuation? It made some very surprising mistakes. My expected output is: I love my version of your couch because you love I, and I'm a couch-lover. The reason I formatted it like this, is because I eventually hope to be able to replace the item.replace(x, y) variables with words in a database.

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  • Global name not defined error in Django/Python trying to set foreignkey

    - by Mark
    Summary: I define a method createPage within a file called PageTree.py that takes a Source model object and a string. The method tries to generate a Page model object. It tries to set the Page model object's foreignkey to refer to the Source model object which was passed in. This throws a NameError exception! I'm trying to represent a website which is structured like a tree. I define the Django models Page and Source, Page representing a node on the tree and Source representing the contents of the page. (You can probably skip over these, this is a basic tree implementation using doubly linked nodes). class Page(models.Model): name = models.CharField(max_length=50) parent = models.ForeignKey("self", related_name="children", null=True); firstChild = models.ForeignKey("self", related_name="origin", null=True); nextSibling = models.ForeignKey("self", related_name="prevSibling", null=True); previousSibling = models.ForeignKey("self", related_name="nxtSibling", null=True); source = models.ForeignKey("Source"); class Source(models.Model): #A source that is non dynamic will be refered to as a static source #Dynamic sources contain locations that are names of functions #Static sources contain locations that are places on disk name = models.CharField(primary_key=True, max_length=50) isDynamic = models.BooleanField() location = models.CharField(max_length=100); I've coded a python program called PageTree.py which allows me to request nodes from the database and manipulate the structure of the tree. Here is the trouble making method: def createPage(pageSource, pageName): page = Page() page.source = pageSource page.name = pageName page.save() return page I'm running this program in a shell through manage.py in Windows 7 manage.py shell from mysite.PageManager.models import Page, Source from mysite.PageManager.PageTree import * ... create someSource = Source(), populate the fields, and save it ... createPage(someSource, "test") ... NameError: global name 'source' is not defined When I type in the function definition for createPage into the shell by hand, the call works without error. This is driving me bonkers and help is appreciated.

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  • Python + Expat: Error on &#0; entities

    - by clacke
    I have written a small function, which uses ElementTree and xpath to extract the text contents of certain elements in an xml file: #!/usr/bin/env python2.5 import doctest from xml.etree import ElementTree from StringIO import StringIO def parse_xml_etree(sin, xpath): """ Takes as input a stream containing XML and an XPath expression. Applies the XPath expression to the XML and returns a generator yielding the text contents of each element returned. >>> parse_xml_etree( ... StringIO('<test><elem1>one</elem1><elem2>two</elem2></test>'), ... '//elem1').next() 'one' >>> parse_xml_etree( ... StringIO('<test><elem1>one</elem1><elem2>two</elem2></test>'), ... '//elem2').next() 'two' >>> parse_xml_etree( ... StringIO('<test><null>&#0;</null><elem3>three</elem3></test>'), ... '//elem2').next() 'three' """ tree = ElementTree.parse(sin) for element in tree.findall(xpath): yield element.text if __name__ == '__main__': doctest.testmod(verbose=True) The third test fails with the following exception: ExpatError: reference to invalid character number: line 1, column 13 Is the � entity illegal XML? Regardless whether it is or not, the files I want to parse contain it, and I need some way to parse them. Any suggestions for another parser than Expat, or settings for Expat, that would allow me to do that?

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  • Rendering partial for table row with form_tag is getting crazy!

    - by xopht
    I have 23(column)x6(row) table and change the row with link_to_remote function. each tr tag has its own id attribute. change link call change action and change action changes the row using render function wit partial. _change.html.erb <td id="row_1">1</td> . . omitted . . <td id="row_23">23</td> link_to_remote function <%= link_to_remote 'Change', :update => 'row_1', :url => change_path %> change action def change logger.debug render :partial => 'change' end If I coded like above, everything work okay. This means all changed-columns are in one row. But, if I wrap partial code with *form_for* function like below... <% form_for 'change' do %> <td id="row_1">1</td> . . omitted . . <td id="row_23">23</td> <% end %> Then, one column located in one row and that column is the first column. I've looked up the log file, but it was normal html tags. What's wrong?

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  • Python coin-toss

    - by Andy
    i am new to Python, and i can't wrap my head around this. I have following function defined: def FlipCoins(num_flips): heads_rounds_won = 0 for i in range(10000): heads = 0 tails = 0 for j in range(num_flips): dice = random.randint(0,1) if dice==1: heads += 1 else: tails += 1 if heads > tails: heads_rounds_won += 1 return heads_rounds_won Here is what it should do (but apparently doesn't): flip a coin num_flip times, count heads and tails, and see if there are more heads than tails. If yes, increment head_rounds_won by 1. Repeat 10000 times. I would assume that head_rounds_won will approximate 5000 (50%). And it does that for odd numbers as input. For example, 3, 5 or 7 will produce about 50%. However, even numbers will produce much lower results, more like 34%. Small numbers especially, with higher even numbers, like for example 800, the difference to 50% is much narrower. Why is this the case? Shouldn't any input produce about 50% heads/tails?

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  • How to control access to third party HTML pages

    - by Wylie
    Hello, We have a Learning Management System (LMS) that runs on its own server (IIS/Server 2003). Students must login with Forms authentication to gain access to the content. We want to offer access to third party flash and audio that is embedded in HTML pages hosted on the third party server (IIS/Server 2003). Currently we use a frame in a pop-up window that is populated via a simple URL to the third party HTML pages. How can the third party control access to their content, so that only students who launch the pop-up windows from our site can access their content? Since the content is mostly video and flash, we would prefer not to stream all of their content through our server to the Student. We have a programming staff, so we could maybe... - either post or get for our HTTP request to the third party server - we could use SSL - we could programmatically assign a global NT user account to all of our users and then do some kind of Active Directory login from the LMS server to the third party server - could the third party content be hosted at Amazon S3? Would this allow for secure access/download? These are just ideas. We really have no idea. Any suggestions would be greatly appreciated. TIA, Wylie

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  • Trie Backtracking in Recursion

    - by Darksky
    I am building a tree for a spell checker with suggestions. Each node contains a key (a letter) and a value (array of letters down that path). So assume the following sub-trie in my big trie: W / \ a e | | k k | | is word--> e e | ... This is just a subpath of a sub-trie. W is a node and a and e are two nodes in its value array etc... At each node, I check if the next letter in the word is a value of the node. I am trying to support mistyped vowels for now. So 'weke' will yield 'wake' as a suggestion. Here's my searchWord function in my trie: def searchWord(self, word, path=""): if len(word) > 0: key = word[0] word = word[1:] if self.values.has_key(key): path = path + key nextNode = self.values[key] return nextNode.searchWord(word, path) else: # check here if key is a vowel. If it is, check for other vowel substitutes else: if self.isWord: return path # this is the word found else: return None Given 'weke', at the end when word is of length zero and path is 'weke', my code will hit the second big else block. weke is not marked as a word and so it will return with None. This will return out of searchWord with None. To avoid this, at each stack unwind or recursion backtrack, I need to check if a letter is a vowel and if it is, do the checking again. I changed the if self.values.has_key(key) loop to the following: if self.values.has_key(key): path = path + key nextNode = self.values[key] ret = nextNode.searchWord(word, path) if ret == None: # check if key == vowel and replace path # return nextNode.searchWord(... return ret What am I doing wrong here? What can I do when backtracking to achieve what I'm trying to do?

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  • wxPython: MainLoop() seems to hang

    - by BandGap
    Hi all, my problem stems from the use of wxApp as far as I can tell. Inside a litte subroutine I call a wx.MessageDialog to ask for a yes or no. I retrieve the answer an process some stuff acordingly. My example code below actually works (though it might be ugly) except that the Dialog box stays open after hitting one of the buttons... import wx from os import path def HasFile(filename): if path.isfile(filename ): app = wx.App() dial = wx.MessageDialog(None, 'Die Datei "'+filename+'" wurde gefunden.\nSoll sie eingelesen werden?', 'Bitte antworten', wx.YES_NO | wx.YES_DEFAULT | wx.ICON_QUESTION) result = dial.ShowModal() dial.EndModal(retCode=0) dial.Destroy() app.MainLoop() return result == wx.ID_YES else: return False So while the rest of the program does whatever is expected, the box just sits there. It also seems like my calls to matplotlib later on are producing errors (a Tkinter error to be precise), maybe because of the wx stuff? Edit: I tried to end the app with a call to app.Destroy(). This doesn't change the fact that the box is still there. When I issue a app.IsActive() afterwards the whole program exits (almost like a sys.exit())! How come? Edit 2: Adding a wxApp like this isn't a good idea since the other scripts get affected as well. Subsequent plotting commands don't get displayed and I don't know how to fix this. Thus I decided to remove the DialogBox alltogether.

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  • Sanitizing User Input with Ruby on Rails

    - by phreakre
    I'm writing a very simple CRUD app that takes user stories and stores them into a database so another fellow coder can organize them for a project we're both working on. However, I have come across a problem with sanitizing user input before it is saved into the database. I cannot call the sanitize() function from within the Story model to strip out all of the html/scripting. It requires me to do the following: def sanitize_inputs self.name = ActionController::Base.helpers.sanitize(self.name) unless self.name.nil? self.story = ActionController::Base.helpers.sanitize(self.story) unless self.story.nil? end I want to validate that the user input has been sanitized and I am unsure of two things: 1) When should the user input validation take place? Before the data is saved is pretty obvious, I think, however, should I be processing this stuff in the Controller, before validation, or some other non-obvious area before I validate that the user input has no scripting/html tags? 2) Writing a unit test for this model, how would I verify that the scripting/html is removed besides comparing "This is a malicious code example" to the sanitize(example) output? Thanks in advance.

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  • Ruby on Rails: custom instance creation failing at redirect

    - by Jack
    I am at an absolute loss as to what I am doing wrong with the following code. I am trying to implement a messaging system within my application, but want it to be handle different types of messages. In this case, I want to create a "request" message of ':message_type = 1'. Instead of using forms as I usually have, I want to make this instance the moment the link is clicked. Here is how I have it set up in the show erb file for "user": <%=link_to "Send friend request", :action=>"request", :controller => "messages", :id => @user.id %> and in the controller: def request @message = Message.new(:sender_id => current_user.id,:user_id => params[:id],:message_type => 1) if @message.save flash[:notice] = 'Message was successfully created.' redirect_to message_path(@message) else redirect_to message_path(@message) end end This results in the following error message: undefined method `rewrite' for nil:NilClass with the trace looking like c:/ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/whiny_nil.rb:52:in `method_missing' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/base.rb:634:in `url_for' (eval):16:in `message_path' app/controllers/messages_controller.rb:11:in `request' I have used map.resources :messages in the routes.rb file, and done the appropriate :has_many and :belongs_to associations in the models of user and message.

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  • Faster quadrature decoder loops with Python code

    - by Kelei
    I'm working with a BeagleBone Black and using Adafruit's IO Python library. Wrote a simple quadrature decoding function and it works perfectly fine when the motor runs at about 1800 RPM. But when the motor runs at higher speeds, the code starts missing some of the interrupts and the encoder counts start to accumulate errors. Do you guys have any suggestions as to how I can make the code more efficient or if there are functions which can cycle the interrupts at a higher frequency. Thanks, Kel Here's the code: # Define encoder count function def encodercount(term): global counts global Encoder_A global Encoder_A_old global Encoder_B global Encoder_B_old global error Encoder_A = GPIO.input('P8_7') # stores the value of the encoders at time of interrupt Encoder_B = GPIO.input('P8_8') if Encoder_A == Encoder_A_old and Encoder_B == Encoder_B_old: # this will be an error error += 1 print 'Error count is %s' %error elif (Encoder_A == 1 and Encoder_B_old == 0) or (Encoder_A == 0 and Encoder_B_old == 1): # this will be clockwise rotation counts += 1 print 'Encoder count is %s' %counts print 'AB is %s %s' % (Encoder_A, Encoder_B) elif (Encoder_A == 1 and Encoder_B_old == 1) or (Encoder_A == 0 and Encoder_B_old == 0): # this will be counter-clockwise rotation counts -= 1 print 'Encoder count is %s' %counts print 'AB is %s %s' % (Encoder_A, Encoder_B) else: #this will be an error as well error += 1 print 'Error count is %s' %error Encoder_A_old = Encoder_A # store the current encoder values as old values to be used as comparison in the next loop Encoder_B_old = Encoder_B # Initialize the interrupts - these trigger on the both the rising and falling GPIO.add_event_detect('P8_7', GPIO.BOTH, callback = encodercount) # Encoder A GPIO.add_event_detect('P8_8', GPIO.BOTH, callback = encodercount) # Encoder B # This is the part of the code which runs normally in the background while True: time.sleep(1)

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  • how to fetch more than 1000 entities NON keybased?

    - by user291071
    If I should be approaching this problem through a different method, please suggest so. I am creating an item based collaborative filter. I populate the db with the LinkRating2 class and for each link there are more than a 1000 users that I need to call and collect their ratings to perform calculations which I then use to create another table. So I need to call more than 1000 entities for a given link. For instance lets say there are over a 1000 users rated 'link1' there will be over a 1000 instances of this class for the given link property that I need to call. How would I complete this example? class LinkRating2(db.Model): user = db.StringProperty() link = db.StringProperty() rating2 = db.FloatProperty() query =LinkRating2.all() link1 = 'link string name' a = query.filter('link = ', link1) aa = a.fetch(1000)##how would i get more than 1000 for a given link1 as shown? ##keybased over 1000 in other post example i need method for a subset though not key class MyModel(db.Expando): @classmethod def count_all(cls): """ Count *all* of the rows (without maxing out at 1000) """ count = 0 query = cls.all().order('__key__') while count % 1000 == 0: current_count = query.count() if current_count == 0: break count += current_count if current_count == 1000: last_key = query.fetch(1, 999)[0].key() query = query.filter('__key__ > ', last_key) return count

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  • Rails creating users, roles, and projects

    - by Bobby
    I am still fairly new to rails and activerecord, so please excuse any oversights. I have 3 models that I'm trying to tie together (and a 4th to actually do the tying) to create a permission scheme using user-defined roles. class User < ActiveRecord::Base has_many :user_projects has_many :projects, :through => :user_projects has_many :project_roles, :through => :user_projects end class Project < ActiveRecord::Base has_many :user_projects has_many :users, :through => :user_projects has_many :project_roles end class ProjectRole < ActiveRecord::Base belongs_to :projects belongs_to :user_projects end class UserProject < ActiveRecord::Base belongs_to :user belongs_to :project has_one :project_role attr_accessible :project_role_id end The project_roles model contains a user-defined role name, and booleans that define whether the given role has permissions for a specific task. I'm looking for an elegant solution to reference that from anywhere within the project piece of my application easily. I do already have a role system implemented for the entire application. What I'm really looking for though is that the users will be able to manage their own roles on a per-project basis. Every project gets setup with an immutable default admin role, and the project creator gets added upon project creation. Since the users are creating the roles, I would like to be able to pull a list of role names from the project and user models through association (for display purposes), but for testing access, I would like to simply reference them by what they have access to without having reference them by name. Perhaps something like this? def has_perm?(permission, user) # The permission that I'm testing user.current_project.project_roles.each do |role| if role.send(permission) # Not sure that's right... do_stuff end end end I think I'm in over my head on this one because I keep running in circles on how I can best implement this.

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  • can I put my sqlite connection and cursor in a function?

    - by steini
    I was thinking I'd try to make my sqlite db connection a function instead of copy/pasting the ~6 lines needed to connect and execute a query all over the place. I'd like to make it versatile so I can use the same function for create/select/insert/etc... Below is what I have tried. The 'INSERT' and 'CREATE TABLE' queries are working, but if I do a 'SELECT' query, how can I work with the values it fetches outside of the function? Usually I'd like to print the values it fetches and also do other things with them. When I do it like below I get an error Traceback (most recent call last): File "C:\Users\steini\Desktop\py\database\test3.py", line 15, in <module> for row in connection('testdb45.db', "select * from users"): ProgrammingError: Cannot operate on a closed database. So I guess the connection needs to be open so I can get the values from the cursor, but I need to close it so the file isn't always locked. Here's my testing code: import sqlite3 def connection (db, arg): conn = sqlite3.connect(db) conn.execute('pragma foreign_keys = on') cur = conn.cursor() cur.execute(arg) conn.commit() conn.close() return cur connection('testdb.db', "create table users ('user', 'email')") connection('testdb.db', "insert into users ('user', 'email') values ('joey', 'foo@bar')") for row in connection('testdb45.db', "select * from users"): print row How can I make this work?

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  • Grails one-to-many mapping with joinTable

    - by intargc
    I have two domain-classes. One is a "Partner" the other is a "Customer". A customer can be a part of a Partner and a Partner can have 1 or more Customers: class Customer { Integer id String name static hasOne = [partner:Partner] static mapping = { partner joinTable:[name:'PartnerMap',column:'partner_id',key:'customer_id'] } } class Partner { Integer id static hasMany = [customers:Customer] static mapping = { customers joinTable:[name:'PartnerMap',column:'customer_id',key:'partner_id'] } } However, whenever I try to see if a customer is a part of a partner, like this: def customers = Customer.list() customers.each { if (it.partner) { println "Partner!" } } I get the following error: org.springframework.dao.InvalidDataAccessResourceUsageException: could not execute query; SQL [select this_.customer_id as customer1_162_0_, this_.company as company162_0_, this_.display_name as display3_162_0_, this_.parent_customer_id as parent4_162_0_, this_.partner_id as partner5_162_0_, this_.server_id as server6_162_0_, this_.status as status162_0_, this_.vertical_market as vertical8_162_0_ from Customer this_]; nested exception is org.hibernate.exception.SQLGrammarException: could not execute query It looks as if Grails is thinking partner_id is a part of the Customer query, and it's not... It is in the PartnerMap table, which is supposed to find the customer_id, then get the Partner from the corresponding partner_id. Anyone have any clue what I'm doing wrong? Edit: I forgot to mention I'm doing this with legacy database tables. So I have a Partner, Customer and PartnerMap table. PartnerMap has simply a customer_id and partner_id field.

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  • Can you dynamically combine multiple conditional functions into one in Python?

    - by erich
    I'm curious if it's possible to take several conditional functions and create one function that checks them all (e.g. the way a generator takes a procedure for iterating through a series and creates an iterator). The basic usage case would be when you have a large number of conditional parameters (e.g. "max_a", "min_a", "max_b", "min_b", etc.), many of which could be blank. They would all be passed to this "function creating" function, which would then return one function that checked them all. Below is an example of a naive way of doing what I'm asking: def combining_function(max_a, min_a, max_b, min_b, ...): f_array = [] if max_a is not None: f_array.append( lambda x: x.a < max_a ) if min_a is not None: f_array.append( lambda x: x.a > min_a ) ... return lambda x: all( [ f(x) for f in f_array ] ) What I'm wondering is what is the most efficient to achieve what's being done above? It seems like executing a function call for every function in f_array would create a decent amount of overhead, but perhaps I'm engaging in premature/unnecessary optimization. Regardless, I'd be interested to see if anyone else has come across usage cases like this and how they proceeded. Also, if this isn't possible in Python, is it possible in other (perhaps more functional) languages?

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  • How do I execute queries upon DB connection in Rails?

    - by sycobuny
    I have certain initializing functions that I use to set up audit logging on the DB server side (ie, not rails) in PostgreSQL. At least one has to be issued (setting the current user) before inserting data into or updating any of the audited tables, or else the whole query will fail spectacularly. I can easily call these every time before running any save operation in the code, but DRY makes me think I should have the code repeated in as few places as possible, particularly since this diverges greatly from the ideal of database agnosticism. Currently I'm attempting to override ActiveRecord::Base.establish_connection in an initializer to set it up so that the queries are run as soon as I connect automatically, but it doesn't behave as I expect it to. Here is the code in the initializer: class ActiveRecord::Base # extend the class methods, not the instance methods class << self alias :old_establish_connection :establish_connection # hide the default def establish_connection(*args) ret = old_establish_connection(*args) # call the default # set up necessary session variables for audit logging # call these after calling default, to make sure conn is established 1st db = self.class.connection db.execute("SELECT SV.set('current_user', 'test@localhost')") db.execute("SELECT SV.set('audit_notes', NULL)") # end "empty variable" err ret # return the default's original value end end end puts "Loaded custom establish_connection into ActiveRecord::Base" sycobuny:~/rails$ ruby script/server = Booting WEBrick = Rails 2.3.5 application starting on http://0.0.0.0:3000 Loaded custom establish_connection into ActiveRecord::Base This doesn't give me any errors, and unfortunately I can't check what the method looks like internally (I was using ActiveRecord::Base.method(:establish_connection), but apparently that creates a new Method object each time it's called, which is seemingly worthless cause I can't check object_id for any worthwhile information and I also can't reverse the compilation). However, the code never seems to get called, because any attempt to run a save or an update on a database object fails as I predicted earlier. If this isn't a proper way to execute code immediately on connection to the database, then what is?

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  • How to define default values optional fields in play framework forms?

    - by natalinobusa
    I am implementing a web api using the scala 2.0.2 play framework. I would like to extract and validate a number of get parameters. And for this I am using a play "form" which allows me to define optional fields. Problem: For those optional fields, I need to define a default value if the parameter is not passed. The code is intended to parse correctly these three use cases: /test?top=abc (error, abc is not an integer) /test?top=123 (valid, top is 123) /test (valid, top is 42 (default value)) I have come up with the following code: def test = Action { implicit request => case class CData(top:Int) val p = Form( mapping( "top" -> optional(number) )((top) => CData($top.getOrElse(42))) ((cdata:CData) => Some(Some(cdata.top))) ).bindFromRequest() Ok("all done.") } The code works, but it's definitely not elegant. There is a lot of boiler plate going on just to set up a default value for a missing request parameter. Can anyone suggest a cleaner and more coincise solution?

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