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  • Suggestions for hosted file sharing services

    - by Jon
    Before I pose my question, I will give some insight as per my scenario: I work for a small business (cost is an important factor) Our bandwidth is limited and would not support an in-house FTP server We need to share files (mostly pdf, inDesign, Illustrator documents) to our clients, and as we expand, we are finding that our current locally-hosted FTP solution is too slow and is becoming a detriment to our sales team. What we need is a remotely hosted solution to share files with our clients, specifically with the following features: Greater than 100gb of secure storage The Ability to distribute unique log in credentials to clients, granting access to a personalized directory or folder, while limiting access to other files on the server. A relatively simple web-based UI for clients with limited computer knowledge We have considered a dedicated remote server, and web-based services (box.net, yousendit.com, onehub.com, filesanywhere.com) but I am unsure as per the direction we should be taking - have I left another solution out? What would you suggest? Thanks in advance.

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  • Can I set up arbitrary filesystem redirection in Windows?

    - by Jon
    I am sitting in front of a Windows 7 machine that has no drive Q:. Is it possible to arrange for accesses to Q:\somedir to be redirected to an arbitrary location on the existing filesystems (for example, C:\Windows)? I would especially like a "set it and forget it" option, if one exists. I am assuming (although I have not tried it) that it is possible to use SUBST to mount an existing (empty, created for this purpose) folder as drive Q: and then MKLINK /J to create a directory symbolic link from Q:\somedir to wherever I want. However, this approach has a couple of drawbacks that I would like to avoid if possible: The drive Q: will be visible in the system. It is not as clean as I would like (removing the mounted folder will break it; a batch script needs to be manually added to the system startup). Is there a better option? If there is none and I am forced to make compromises, what is the closest I could get to the ideal solution? Assume anything is up for discussion.

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  • View old Inbox messages in (OS X) Mail.app via Exchange IMAP?

    - by Jon-Eric
    We're thinking of migrating our Mac users away from Entourage 2008 and instead using Mail.app (built into OS X Snow Leopard). We're running SBS 2003 so it's Exchange 2003 for now. When I setup an "Exchange IMAP" Mail account for a user, their Inbox shows up as empty. However, all of their other folders appear to be populated with their existing email correctly. New email shows up correctly in their Inbox. What do you have to do to see all of the old messages already in the Inbox? Thank you.

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  • Why don't cfn-init logs get sent by rsyslog?

    - by Jon M
    I just signed up for Papertrail to aggregate logs from some AWS instances I'm setting up with CloudFormation::Init. I've followed the instructions and added *.* @logs.papertrailapp.com to the end of '/etc/rsyslog.conf'. Some logs are showing up on Papertrail, but notably the contents of '/var/log/cfn-init.log' never get there, and those are the ones I'm interested in right now. Have I set up rsyslog incorrectly? Or do the CloudFormation::Init scripts just not use syslog to write log information?

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  • What does it mean for a computer to be an "IBM Compatible PC"?

    - by Jon
    A couple questions about this: 1) Is this term even relevant any more? 2) Does this mean anything from a developer's stand point? It is not exactly clear to me if this is a BIOS, architecture, bus or a combination. A piece of software I'm working on expects to see a "Description" of the system and currently windows machines report "AT/AT Compatible". Having been tasked to port this to Mac, I really don't know what a proper "Description" would be - this will most likely be omitted but I was wondering if anyone could provide some insight on the modern usage of this term.

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  • Windows 7 sound control is not flexible.

    - by jon
    I would like to be able to listen to music on both of two audio output devices, but Windows 7 seems to only allow me to select one or the other as the Default device. When device A is the Default device, device B is muted; and vice versa. This seems to be stunningly inflexible. Since Windows 7 is unable to do this, can anyone recommend any add-on software that would control the hardware more flexibly and thoughtfully?

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  • Strange problem of wifi keeps droping every minute on Ubuntu 12.04

    - by user965884
    I am running ubuntu 12.04 on my samsung laptop but the wifi connection keeps dropping every minute. I have another dell laptop which also has ubuntu 12.04 but wifi works fine on that. And if I use my samsung laptop at office as its my office laptop wifi works fine. So, I don't understand what the problem is. I have googled it and found solution like set ignoring IPv6 setting but that still does not make any difference. So I don't understand where the problem is if its with my network provider or its with my laptop. I can't blame my network provider as wifi works fine on my other devices including Ipad, mobiles and dell laptop. Even I can't say clearly that its problem with my laptop as wifi works fine in my office. Previously I had ubuntu 13.04 on my samsung laptop and I was having the same issue so I uninstall it and install 12.04 and issues is still the same.

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  • C# file Decryption - Bad Data

    - by Jon
    Hi all, I am in the process of rewriting an old application. The old app stored data in a scoreboard file that was encrypted with the following code: private const String SSecretKey = @"?B?n?Mj?"; public DataTable GetScoreboardFromFile() { FileInfo f = new FileInfo(scoreBoardLocation); if (!f.Exists) { return setupNewScoreBoard(); } DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); //A 64 bit key and IV is required for this provider. //Set secret key For DES algorithm. DES.Key = ASCIIEncoding.ASCII.GetBytes(SSecretKey); //Set initialization vector. DES.IV = ASCIIEncoding.ASCII.GetBytes(SSecretKey); //Create a file stream to read the encrypted file back. FileStream fsread = new FileStream(scoreBoardLocation, FileMode.Open, FileAccess.Read); //Create a DES decryptor from the DES instance. ICryptoTransform desdecrypt = DES.CreateDecryptor(); //Create crypto stream set to read and do a //DES decryption transform on incoming bytes. CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read); DataTable dTable = new DataTable("scoreboard"); dTable.ReadXml(new StreamReader(cryptostreamDecr)); cryptostreamDecr.Close(); fsread.Close(); return dTable; } This works fine. I have copied the code into my new app so that I can create a legacy loader and convert the data into the new format. The problem is I get a "Bad Data" error: System.Security.Cryptography.CryptographicException was unhandled Message="Bad Data.\r\n" Source="mscorlib" The error fires at this line: dTable.ReadXml(new StreamReader(cryptostreamDecr)); The encrypted file was created today on the same machine with the old code. I guess that maybe the encryption / decryption process uses the application name / file or something and therefore means I can not open it. Does anyone have an idea as to: A) Be able explain why this isn't working? B) Offer a solution that would allow me to be able to open files that were created with the legacy application and be able to convert them please? Thank you

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  • Java getInputStreat SocketTimeoutException instead of NoRouteToHostException

    - by Jon
    I have an odd issue happening when trying to open multiple Input Streams (in separate threads) on Linux (RHEL). The behaviour works as expected on windows. I am kicking off 3 threads to open https connections to 3 different servers. All three are invalid IP addresses (in this test case), so I expect an NoRouteToHostException for each of them. The first two return these as expected, and quite quickly. (see stack trace below) However the third (and 4th when I tested it that way) do NOT give a no route exception. They wait for ages, and then give a SocketTimeoutException (see other stack trace below). This takes ages to come back, and does not accurately express the connection issue. The offending line of code is: reader = new BufferedReader(new InputStreamReader(conn.getInputStream())); Has anyone seen something like this before? Are there multi-threading issues with sockets on REHL or some limit somewhere to how many can connect at once...or...something? Expected stack trace, as received for first two: java.net.NoRouteToHostException: No route to host at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:559) at sun.net.NetworkClient.doConnect(NetworkClient.java:158) at sun.net.www.http.HttpClient.openServer(HttpClient.java:394) at sun.net.www.http.HttpClient.openServer(HttpClient.java:529) at sun.net.www.protocol.https.HttpsClient.(HttpsClient.java:272) at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:329) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:916) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1177) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:234) Unexpected stack trace, as received on 3rd: java.net.SocketTimeoutException: connect timed out at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:559) at sun.net.NetworkClient.doConnect(NetworkClient.java:158) at sun.net.www.http.HttpClient.openServer(HttpClient.java:394) at sun.net.www.http.HttpClient.openServer(HttpClient.java:529) at sun.net.www.protocol.https.HttpsClient.(HttpsClient.java:272) at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:329) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172) at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:916) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1177) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:234)

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  • Input string was not in a correct format.

    - by Jon
    I have this error which doesn't happen on my local machine but it does when the code is built by our build sever and deployed to the target server. I can't work out what the problem is, after having spent many hours on this issue. Here is an error trace: [FormatException: Input string was not in a correct format.] System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) +7469351 System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) +119 System.Byte.Parse(String s, NumberStyles style, NumberFormatInfo info) +35 System.String.System.IConvertible.ToByte(IFormatProvider provider) +46 System.Convert.ChangeType(Object value, TypeCode typeCode, IFormatProvider provider) +199 System.Web.UI.WebControls.Parameter.GetValue(Object value, String defaultValue, TypeCode type, Boolean convertEmptyStringToNull, Boolean ignoreNullableTypeChanges) +127 System.Web.UI.WebControls.Parameter.GetValue(Object value, Boolean ignoreNullableTypeChanges) +66 System.Web.UI.WebControls.ParameterCollection.GetValues(HttpContext context, Control control) +285 System.Web.UI.WebControls.SqlDataSourceView.InitializeParameters(DbCommand command, ParameterCollection parameters, IDictionary exclusionList) +251 System.Web.UI.WebControls.SqlDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +476 System.Web.UI.WebControls.SqlDataSource.Select(DataSourceSelectArguments arguments) +19 Customer_NewTenancyList.BindReport(GridSortEventArgs e) +442 Customer_NewTenancyList.Page_Load(Object sender, EventArgs e) +345 System.Web.UI.Control.OnLoad(EventArgs e) +73 baseRslpage.OnLoad(EventArgs e) +16 System.Web.UI.Control.LoadRecursive() +52 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2170 Here is my own trace: Begin PreInit aspx.page End PreInit 3.12888928620816E-05 0.000031 aspx.page Begin Init 7.43111205474439E-05 0.000043 aspx.page End Init 0.00122138428208054 0.001147 aspx.page Begin InitComplete 0.00125379063540199 0.000032 aspx.page End InitComplete 0.00127781603527823 0.000024 aspx.page Begin PreLoad 0.00131022238859967 0.000032 aspx.page End PreLoad 0.00133424778847591 0.000024 aspx.page Begin Load 0.00135575890231859 0.000022 Page_Load 0.00145996209015392 0.000104 BindReport 0.0014856636807192 0.000026 Parameters add start: 30/03/2010 30/04/2010 0.0015569017850034 0.000071 Parameters add ended 0.00160048274291844 0.000044 Trace 1 0.00162450814279468 0.000024 Unhandled Execution Error Input string was not in a correct format. at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) at System.Byte.Parse(String s, NumberStyles style, NumberFormatInfo info) at System.String.System.IConvertible.ToByte(IFormatProvider provider) at System.Convert.ChangeType(Object value, TypeCode typeCode, IFormatProvider provider) at System.Web.UI.WebControls.Parameter.GetValue(Object value, String defaultValue, TypeCode type, Boolean convertEmptyStringToNull, Boolean ignoreNullableTypeChanges) at System.Web.UI.WebControls.Parameter.GetValue(Object value, Boolean ignoreNullableTypeChanges) at System.Web.UI.WebControls.ParameterCollection.GetValues(HttpContext context, Control control) at System.Web.UI.WebControls.SqlDataSourceView.InitializeParameters(DbCommand command, ParameterCollection parameters, IDictionary exclusionList) at System.Web.UI.WebControls.SqlDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) at System.Web.UI.WebControls.SqlDataSource.Select(DataSourceSelectArguments arguments) at Customer_NewTenancyList.BindReport(GridSortEventArgs e) at Customer_NewTenancyList.Page_Load(Object sender, EventArgs e) at System.Web.UI.Control.OnLoad(EventArgs e) at baseRslpage.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) And here is my code: Trace.Warn("BindReport") Dim sds As New SqlDataSource sds.SelectCommand = "C_MYSTORED_PROC" sds.ConnectionString = ConfigurationManager.ConnectionStrings("connstring").ConnectionString sds.SelectCommandType = SqlDataSourceCommandType.StoredProcedure Trace.Warn(String.Format("Parameters add start: {0} {1}", dpFrom.Text, dpTo.Text)) sds.SelectParameters.Add(New Parameter("FROMDATE", DbType.DateTime, dpFrom.Text)) sds.SelectParameters.Add(New Parameter("TODATE", DbType.DateTime, dpTo.Text)) Trace.Warn("Parameters add ended") Dim dv As DataView Dim dt As DataTable Trace.Warn("Trace 1") dv = sds.Select(New DataSourceSelectArguments()) Trace.Warn("Trace 2") If e IsNot Nothing Then dv.Sort = String.Format("{0} {1}", e.SortField, e.SortDirection) Trace.Warn("Trace 3") Else gvReport.CurrentSortColumnIndex = 0 gvReport.Columns(0).SortDirection = "DESC" Trace.Warn("Trace 4") End If Trace.Warn("Trace 5") dt = dv.ToTable() Cache("NewTenancyList") = dt Trace.Warn("Trace 6") Trace.Warn("About to databind") gvReport.DataSource = dt gvReport.DataBind() Trace.Warn("Databinded") What I don't understand and this is really weird, why does it work on my local machine but not on the live server? If i build the code on my local machine then copy over the complete \bin directory it works. If I pull the code from source safe, build then copy, I get this error. It seems to choke after the line "dv = sds.Select(New DataSourceSelectArguments())" in the code.

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  • Big sinatra problems

    - by Joel M.
    Hi, So I'm having huge trouble with sinatra. Here's what I have: require 'dm-core' DataMapper.setup(:default, ENV['DATABASE_URL'] || 'sqlite3://my.db') class Something include DataMapper::Resource property :id, Serial property :thing, Text property :run_in, Integer property :added_at, DateTime property :to, String def schedule cronify(self.thing+" to "+self.to, "http://url"+self.id.to_s, self.run_in) end def notify text(self.thing, self.to) end end Something.auto_upgrade! The cronify method works. I tested it in irb. Also, the schedule instance method works, I tested it in the console. However, it doesn't work in the route, even though it works in the console. post '/add' do @something = Something.create(blah) #this works fine @something.schedule #this works fine in the console; not in the route. end I've tried everything, from @something.create(blah).schedule (which also works fine in the console, but not in the route), to defining the method cronify inside the sinatra helpers, and even calling cronify directly on the route. Nothing works on the route. What am I doing wrong?

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  • JPA IndirectSet changes not reflected in Spring frontend

    - by Jon
    I'm having an issue with Spring JPA and IndirectSets. I have two entities, Parent and Child, defined below. I have a Spring form in which I'm trying to create a new Child and link it to an existing Parent, then have everything reflected in the database and in the web interface. What's happening is that it gets put into the database, but the UI doesn't seem to agree. The two entities that are linked to each other in a OneToMany relationship like so: @Entity @Table(name = "parent", catalog = "myschema", uniqueConstraints = @UniqueConstraint(columnNames = "ChildLinkID")) public class Parent { private Integer id; private String childLinkID; private Set<Child> children = new HashSet<Child>(0); @Id @GeneratedValue(strategy = IDENTITY) @Column(name = "id", unique = true, nullable = false) public Integer getId() { return this.id; } public void setId(Integer id) { this.id = id; } @Column(name = "ChildLinkID", unique = true, nullable = false, length = 6) public String getChildLinkID() { return this.childLinkID; } public void setChildLinkID(String childLinkID) { this.childLinkID = childLinkID; } @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "parent") public Set<Child> getChildren() { return this.children; } public void setChildren(Set<Child> children) { this.children = children; } } @Entity @Table(name = "child", catalog = "myschema") public class Child extends private Integer id; private Parent parent; @Id @GeneratedValue(strategy = IDENTITY) @Column(name = "id", unique = true, nullable = false) public Integer getId() { return this.id; } public void setId(Integer id) { this.id = id; } @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "ChildLinkID", referencedColumnName = "ChildLinkID", nullable = false) public Parent getParent() { return this.parent; } public void setParent(Parent parent) { this.parent = parent; } } And of course, assorted simple properties on each of them. Now, the problem is that when I edit those simple properties from my Spring interface, everything works beautifully. I can persist new entities of these types and they'll appear when using the JPATemplate to do a find on, say, all Parents (getJpaTemplate().find("select p from Parent p")) or on individual entities by ID or another property. The problem I'm running into is that now, I'm trying to create a new Child linked to an existing Parent through a link from the Parent's page. Here's the important bits of the Controller (note that I've placed the JPA foo in the controller here to make it clearer; the actual JpaDaoSupport is actually in another class, appropriately tiered): protected Object formBackingObject(HttpServletRequest request) throws Exception { String parentArg = request.getParameter("parent"); int parentId = Integer.parseInt(parentArg); Parent parent = getJpaTemplate().find(Parent.class, parentId); Child child = new Child(); child.setParent(parent); NewChildCommand command = new NewChildCommand(); command.setChild(child); return command; } protected ModelAndView onSubmit(Object cmd) throws Exception { NewChildCommand command = (NewChildCommand)cmd; Child child = command.getChild(); child.getParent().getChildren().add(child); getJpaTemplate().merge(child); return new ModelAndView(new RedirectView(getSuccessView())); } Like I said, I can run through the form and fill in the new values for the Child -- the Parent's details aren't even displayed. When it gets back to the controller, it goes through and saves it to the underlying database, but the interface never reflects it. Once I restart the app, it's all there and populated appropriately. What can I do to clear this up? I've tried to call extra merges, tried refreshes (which gave a transaction exception), everything short of just writing my own database access code. I've made sure that every class has an appropriate equals() and hashCode(), have full JPA debugging on to see that it's making appropriate SQL calls (it doesn't seem to make any new calls to the Child table) and stepped through in the debugger (it's all in IndirectSets, as expected, and between saving and displaying the Parent the object takes on a new memory address). What's my next step?

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  • Why doesn't my QsciLexerCustom subclass work in PyQt4 using QsciScintilla?

    - by Jon Watte
    My end goal is to get Erlang syntax highlighting in QsciScintilla using PyQt4 and Python 2.6. I'm running on Windows 7, but will also need Ubuntu support. PyQt4 is missing the necessary wrapper code for the Erlang lexer/highlighter that "base" scintilla has, so I figured I'd write a lightweight one on top of QsciLexerCustom. It's a little bit problematic, because the Qsci wrapper seems to really want to talk about line+index rather than offset-from-start when getting/setting subranges of text. Meanwhile, the lexer gets arguments as offset-from-start. For now, I get a copy of the entire text, and split that up as appropriate. I have the following lexer, and I apply it with setLexer(). It gets all the appropriate calls when I open a new file and sets this as the lexer, and prints a bunch of appropriate lines based on what it's doing... but there is no styling in the document. I tried making all the defined styles red, and the document is still stubbornly black-on-white, so apparently the styles don't really "take effect" What am I doing wrong? If nobody here knows, what's the appropriate discussion forum where people might actually know these things? (It's an interesting intersection between Python, Qt and Scintilla, so I imagine the set of people who would know is small) Let's assume prefs.declare() just sets up a dict that returns the value for the given key (I've verified this -- it's not the problem). Let's assume scintilla is reasonably properly constructed into its host window QWidget. Specifically, if I apply a bundled lexer (such as QsciLexerPython), it takes effect and does show styled text. prefs.declare('font.name.margin', "MS Dlg") prefs.declare('font.size.margin', 8) prefs.declare('font.name.code', "Courier New") prefs.declare('font.size.code', 10) prefs.declare('color.editline', "#d0e0ff") class LexerErlang(Qsci.QsciLexerCustom): def __init__(self, obj = None): Qsci.QsciLexerCustom.__init__(self, obj) self.sci = None self.plainFont = QtGui.QFont() self.plainFont.setPointSize(int(prefs.get('font.size.code'))) self.plainFont.setFamily(prefs.get('font.name.code')) self.marginFont = QtGui.QFont() self.marginFont.setPointSize(int(prefs.get('font.size.code'))) self.marginFont.setFamily(prefs.get('font.name.margin')) self.boldFont = QtGui.QFont() self.boldFont.setPointSize(int(prefs.get('font.size.code'))) self.boldFont.setFamily(prefs.get('font.name.code')) self.boldFont.setBold(True) self.styles = [ Qsci.QsciStyle(0, QtCore.QString("base"), QtGui.QColor("#000000"), QtGui.QColor("#ffffff"), self.plainFont, True), Qsci.QsciStyle(1, QtCore.QString("comment"), QtGui.QColor("#008000"), QtGui.QColor("#eeffee"), self.marginFont, True), Qsci.QsciStyle(2, QtCore.QString("keyword"), QtGui.QColor("#000080"), QtGui.QColor("#ffffff"), self.boldFont, True), Qsci.QsciStyle(3, QtCore.QString("string"), QtGui.QColor("#800000"), QtGui.QColor("#ffffff"), self.marginFont, True), Qsci.QsciStyle(4, QtCore.QString("atom"), QtGui.QColor("#008080"), QtGui.QColor("#ffffff"), self.plainFont, True), Qsci.QsciStyle(5, QtCore.QString("macro"), QtGui.QColor("#808000"), QtGui.QColor("#ffffff"), self.boldFont, True), Qsci.QsciStyle(6, QtCore.QString("error"), QtGui.QColor("#000000"), QtGui.QColor("#ffd0d0"), self.plainFont, True), ] print("LexerErlang created") def description(self, ix): for i in self.styles: if i.style() == ix: return QtCore.QString(i.description()) return QtCore.QString("") def setEditor(self, sci): self.sci = sci Qsci.QsciLexerCustom.setEditor(self, sci) print("LexerErlang.setEditor()") def styleText(self, start, end): print("LexerErlang.styleText(%d,%d)" % (start, end)) lines = self.getText(start, end) offset = start self.startStyling(offset, 0) print("startStyling()") for i in lines: if i == "": self.setStyling(1, self.styles[0]) print("setStyling(1)") offset += 1 continue if i[0] == '%': self.setStyling(len(i)+1, self.styles[1]) print("setStyling(%)") offset += len(i)+1 continue self.setStyling(len(i)+1, self.styles[0]) print("setStyling(n)") offset += len(i)+1 def getText(self, start, end): data = self.sci.text() print("LexerErlang.getText(): " + str(len(data)) + " chars") return data[start:end].split('\n') Applied to the QsciScintilla widget as follows: _lexers = { 'erl': (Q.SCLEX_ERLANG, LexerErlang), 'hrl': (Q.SCLEX_ERLANG, LexerErlang), 'html': (Q.SCLEX_HTML, Qsci.QsciLexerHTML), 'css': (Q.SCLEX_CSS, Qsci.QsciLexerCSS), 'py': (Q.SCLEX_PYTHON, Qsci.QsciLexerPython), 'php': (Q.SCLEX_PHP, Qsci.QsciLexerHTML), 'inc': (Q.SCLEX_PHP, Qsci.QsciLexerHTML), 'js': (Q.SCLEX_CPP, Qsci.QsciLexerJavaScript), 'cpp': (Q.SCLEX_CPP, Qsci.QsciLexerCPP), 'h': (Q.SCLEX_CPP, Qsci.QsciLexerCPP), 'cxx': (Q.SCLEX_CPP, Qsci.QsciLexerCPP), 'hpp': (Q.SCLEX_CPP, Qsci.QsciLexerCPP), 'c': (Q.SCLEX_CPP, Qsci.QsciLexerCPP), 'hxx': (Q.SCLEX_CPP, Qsci.QsciLexerCPP), 'tpl': (Q.SCLEX_CPP, Qsci.QsciLexerCPP), 'xml': (Q.SCLEX_XML, Qsci.QsciLexerXML), } ... inside my document window class ... def addContentsDocument(self, contents, title): handler = self.makeScintilla() handler.title = title sci = handler.sci sci.append(contents) self.tabWidget.addTab(sci, title) self.tabWidget.setCurrentWidget(sci) self.applyLexer(sci, title) EventBus.bus.broadcast('command.done', {'text': 'Opened ' + title}) return handler def applyLexer(self, sci, title): (language, lexer) = language_and_lexer_from_title(title) if lexer: l = lexer() print("making lexer: " + str(l)) sci.setLexer(l) else: print("setting lexer by id: " + str(language)) sci.SendScintilla(Qsci.QsciScintillaBase.SCI_SETLEXER, language) linst = sci.lexer() print("lexer: " + str(linst)) def makeScintilla(self): sci = Qsci.QsciScintilla() sci.setUtf8(True) sci.setTabIndents(True) sci.setIndentationsUseTabs(False) sci.setIndentationWidth(4) sci.setMarginsFont(self.smallFont) sci.setMarginWidth(0, self.smallFontMetrics.width('00000')) sci.setFont(self.monoFont) sci.setAutoIndent(True) sci.setBraceMatching(Qsci.QsciScintilla.StrictBraceMatch) handler = SciHandler(sci) self.handlers[sci] = handler sci.setMarginLineNumbers(0, True) sci.setCaretLineVisible(True) sci.setCaretLineBackgroundColor(QtGui.QColor(prefs.get('color.editline'))) return handler Let's assume the rest of the application works, too (because it does :-)

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  • Can I check the validity of a single DataMapper property?

    - by Nathan Long
    In a custom DataMapper setter, I'd like to check whether the value I'm setting is valid or not. For instance: class ToastMitten include DataMapper::Resource property :id, Serial property :wearer, Enum['Chuck Norris', 'Jon Skeet'] property :first_worn_at, DateTime def wearer=(name) super if wearer.valid? # How can I do this? first_worn_at = Time.now end end end t = ToastMitten.new t.wearer = 'Nathan Long' # invalid value; do NOT set first_worn_at t.wearer = 'Jon Skeet' # valid value; set first_worn_at Can I check the validity of a single property like this without calling valid? on the object itself and looking through all the errors?

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  • How do we group in BIRT without wasting lines, and still only printing the group item on the first l

    - by paxdiablo
    When grouping in BIRT, we frequently want the grouping value to show up on the first line as follows: Group User Reputation ------ --------------- ---------- Admins Bill The Weasel 51,018 Mark Grovel 118,101 Users pax_my_bags 73,554 Jon Scoot **,***,*** <- overflow clueless 92,928 The normal way of acheiving this is to lay out the group in the designer as follws: +---------+--------+--------------+ Tbl Hdr | Group | User | Reputation | +---------+--------+--------------+ Grp Hdr | [Group] | | | +---------+--------+--------------+ Grp Dtl | | [User] | [Reputation] | +---------+--------+--------------+ Grp Ftr | | | | +---------+--------+--------------+ Tbl Ftr | | | | +---------+--------+--------------+ which, unfortunately, lays out the data in exactly that way, with the grouped value on a different line: Group User Reputation ------ --------------- ---------- Admins Bill The Weasel 51,018 Mark Grovel 118,101 Users pax_my_bags 73,554 Jon Scoot **,***,*** <- overflow clueless 92,928 This is particularly painful with data where there's lots of groups with only one user since we use twice as much space as needed. If we move the [Group] data item down to the Grp Dtl line, we get it printed for every line in the group. How, in BIRT, do we merge the two lines Grp Hdr and the first Grp Dtl?

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  • How to stop .Net HttpWebRequest.GetResponse() raising an exception

    - by James
    Surely, surely, surely there is a way to configure the .Net HttpWebRequest object so that it does not raise an exception when HttpWebRequest.GetResponse() is called and any 300 or 400 status codes are returned? Jon Skeet does not think so, so I almost dare not even ask, but I find it hard to believe there is no way around this. 300 and 400 response codes are valid responses in certain circumstances. Why would we be always forced to incur the overhead of an exception? Perhaps there is some obscure configuration setting that evaded Jon Skeet? Perhaps there is a completely different type of request object that can be used that does not have this behavior? (and yes, I know you can just catch the exception and get the response from that, but I would like to find a way not to have to). Thanks for any help

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  • Safely convert UTC datetimes to local time (based on TZ) for calculations?

    - by James
    Following from my last question which @Jon Skeet gave me a lot of help with (thanks again!) I am now wondering how I can safely work with date/times, stored as UTC, when they are converted back to Local Date/Time. As Jon indicated in my last question using DateTimeOffset represents an instant in time and there is no way to predict what the local time would be say a minute later. I need to be able to do calculations based on these date/times. So how can I assure when I pull the dates from the database, convert them to local date/time and do specific calculations on them they are going to be accurate?

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  • .NET file Decryption - Bad Data

    - by Jon
    I am in the process of rewriting an old application. The old app stored data in a scoreboard file that was encrypted with the following code: private const String SSecretKey = @"?B?n?Mj?"; public DataTable GetScoreboardFromFile() { FileInfo f = new FileInfo(scoreBoardLocation); if (!f.Exists) { return setupNewScoreBoard(); } DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); //A 64 bit key and IV is required for this provider. //Set secret key For DES algorithm. DES.Key = ASCIIEncoding.ASCII.GetBytes(SSecretKey); //Set initialization vector. DES.IV = ASCIIEncoding.ASCII.GetBytes(SSecretKey); //Create a file stream to read the encrypted file back. FileStream fsread = new FileStream(scoreBoardLocation, FileMode.Open, FileAccess.Read); //Create a DES decryptor from the DES instance. ICryptoTransform desdecrypt = DES.CreateDecryptor(); //Create crypto stream set to read and do a //DES decryption transform on incoming bytes. CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read); DataTable dTable = new DataTable("scoreboard"); dTable.ReadXml(new StreamReader(cryptostreamDecr)); cryptostreamDecr.Close(); fsread.Close(); return dTable; } This works fine. I have copied the code into my new app so that I can create a legacy loader and convert the data into the new format. The problem is I get a "Bad Data" error: System.Security.Cryptography.CryptographicException was unhandled Message="Bad Data.\r\n" Source="mscorlib" The error fires at this line: dTable.ReadXml(new StreamReader(cryptostreamDecr)); The encrypted file was created today on the same machine with the old code. I guess that maybe the encryption / decryption process uses the application name / file or something and therefore means I can not open it. Does anyone have an idea as to: A) Be able explain why this isn't working? B) Offer a solution that would allow me to be able to open files that were created with the legacy application and be able to convert them please? Here is the whole class that deals with loading and saving the scoreboard: using System; using System.Collections.Generic; using System.Text; using System.Security.Cryptography; using System.Runtime.InteropServices; using System.IO; using System.Data; using System.Xml; using System.Threading; namespace JawBreaker { [Serializable] class ScoreBoardLoader { private Jawbreaker jawbreaker; private String sSecretKey = @"?B?n?Mj?"; private String scoreBoardFileLocation = ""; private bool keepScoreBoardUpdated = true; private int intTimer = 180000; public ScoreBoardLoader(Jawbreaker jawbreaker, String scoreBoardFileLocation) { this.jawbreaker = jawbreaker; this.scoreBoardFileLocation = scoreBoardFileLocation; } // Call this function to remove the key from memory after use for security [System.Runtime.InteropServices.DllImport("KERNEL32.DLL", EntryPoint = "RtlZeroMemory")] public static extern bool ZeroMemory(IntPtr Destination, int Length); // Function to Generate a 64 bits Key. private string GenerateKey() { // Create an instance of Symetric Algorithm. Key and IV is generated automatically. DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create(); // Use the Automatically generated key for Encryption. return ASCIIEncoding.ASCII.GetString(desCrypto.Key); } public void writeScoreboardToFile() { DataTable tempScoreBoard = getScoreboardFromFile(); //add in the new scores to the end of the file. for (int i = 0; i < jawbreaker.Scoreboard.Rows.Count; i++) { DataRow row = tempScoreBoard.NewRow(); row.ItemArray = jawbreaker.Scoreboard.Rows[i].ItemArray; tempScoreBoard.Rows.Add(row); } //before it is written back to the file make sure we update the sync info if (jawbreaker.SyncScoreboard) { //connect to webservice, login and update all the scores that have not been synced. for (int i = 0; i < tempScoreBoard.Rows.Count; i++) { try { //check to see if that row has been synced to the server if (!Boolean.Parse(tempScoreBoard.Rows[i].ItemArray[7].ToString())) { //sync info to server //update the row to say that it has been updated object[] tempArray = tempScoreBoard.Rows[i].ItemArray; tempArray[7] = true; tempScoreBoard.Rows[i].ItemArray = tempArray; tempScoreBoard.AcceptChanges(); } } catch (Exception ex) { jawbreaker.writeErrorToLog("ERROR OCCURED DURING SYNC TO SERVER UPDATE: " + ex.Message); } } } FileStream fsEncrypted = new FileStream(scoreBoardFileLocation, FileMode.Create, FileAccess.Write); DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey); DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey); ICryptoTransform desencrypt = DES.CreateEncryptor(); CryptoStream cryptostream = new CryptoStream(fsEncrypted, desencrypt, CryptoStreamMode.Write); MemoryStream ms = new MemoryStream(); tempScoreBoard.WriteXml(ms, XmlWriteMode.WriteSchema); ms.Position = 0; byte[] bitarray = new byte[ms.Length]; ms.Read(bitarray, 0, bitarray.Length); cryptostream.Write(bitarray, 0, bitarray.Length); cryptostream.Close(); ms.Close(); //now the scores have been added to the file remove them from the datatable jawbreaker.Scoreboard.Rows.Clear(); } public void startPeriodicScoreboardWriteToFile() { while (keepScoreBoardUpdated) { //three minute sleep. Thread.Sleep(intTimer); writeScoreboardToFile(); } } public void stopPeriodicScoreboardWriteToFile() { keepScoreBoardUpdated = false; } public int IntTimer { get { return intTimer; } set { intTimer = value; } } public DataTable getScoreboardFromFile() { FileInfo f = new FileInfo(scoreBoardFileLocation); if (!f.Exists) { jawbreaker.writeInfoToLog("Scoreboard not there so creating new one"); return setupNewScoreBoard(); } else { DESCryptoServiceProvider DES = new DESCryptoServiceProvider(); //A 64 bit key and IV is required for this provider. //Set secret key For DES algorithm. DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey); //Set initialization vector. DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey); //Create a file stream to read the encrypted file back. FileStream fsread = new FileStream(scoreBoardFileLocation, FileMode.Open, FileAccess.Read); //Create a DES decryptor from the DES instance. ICryptoTransform desdecrypt = DES.CreateDecryptor(); //Create crypto stream set to read and do a //DES decryption transform on incoming bytes. CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read); DataTable dTable = new DataTable("scoreboard"); dTable.ReadXml(new StreamReader(cryptostreamDecr)); cryptostreamDecr.Close(); fsread.Close(); return dTable; } } public DataTable setupNewScoreBoard() { //scoreboard info into dataset DataTable scoreboard = new DataTable("scoreboard"); scoreboard.Columns.Add(new DataColumn("playername", System.Type.GetType("System.String"))); scoreboard.Columns.Add(new DataColumn("score", System.Type.GetType("System.Int32"))); scoreboard.Columns.Add(new DataColumn("ballnumber", System.Type.GetType("System.Int32"))); scoreboard.Columns.Add(new DataColumn("xsize", System.Type.GetType("System.Int32"))); scoreboard.Columns.Add(new DataColumn("ysize", System.Type.GetType("System.Int32"))); scoreboard.Columns.Add(new DataColumn("gametype", System.Type.GetType("System.String"))); scoreboard.Columns.Add(new DataColumn("date", System.Type.GetType("System.DateTime"))); scoreboard.Columns.Add(new DataColumn("synced", System.Type.GetType("System.Boolean"))); scoreboard.AcceptChanges(); return scoreboard; } private void Run() { // For additional security Pin the key. GCHandle gch = GCHandle.Alloc(sSecretKey, GCHandleType.Pinned); // Remove the Key from memory. ZeroMemory(gch.AddrOfPinnedObject(), sSecretKey.Length * 2); gch.Free(); } } }

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  • Implementing an async "read all currently available data from stream" operation

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a console's standard output Stream. Console output streams are of type FileStream; the implementation can cast to that, if needed. There is also an associated StreamReader already present to leverage. There is only one thing I need to implement in this class to achieve my desired functionality: an async "read all the data available this moment" operation. Reading to the end of the stream is not viable because the stream will not end unless the process closes the console output handle, and it will not do that because it is interactive and expecting input before continuing. I will be using that hypothetical async operation to implement event-based notification, which will be more convenient for my callers. The public interface of the class is this: public class ConsoleAutomator { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Remember that the goal here is to read all of the chunk and call event subscribers exactly once for each chunk. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream. private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer (in which case we know that there was no more data to be read during the last read operation), all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Never more than one event for each time data is available to be read Is almost agnostic to the buffer size The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this. Update: I definitely did not communicate the scenario well in my initial writeup. I have since revised the writeup quite a bit, but to be extra sure: The question is about how to implement an async "read all the data available this moment" operation. My apologies to the people who took the time to read and answer without me making my intent clear enough.

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  • Implementing a robust async stream reader

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output, but that is a detail and does not play an important role. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • Implementing a robust async stream reader for a console

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • Problem restoring from tar backup: why are there /dev/disk/by-id/ symlinks and how can I avoid them?

    - by SK.
    Hello, I'm trying to make a bare-bone backup system with the most basic tools available on openSUSE 11.3 (in this case: bash, fdisk, tar & grub legacy) Here's the workflow for my scripts: backup.sh: (Run from external system, e.g. LiveCD) make an fdisk script ($fscript) from fdisk -l's output [works] mount the partitions from the system's fstab [works] tar the crucial stuff in file.tgz [works] restore.sh: (Run from external system, e.g. LiveCD) run fdisk $dest < $fscript to restore partitioning [works] format and mount partitions from system's fstab [fails] extract from file.tgz [works when mounting manually] restore grub [fails] I have recently noticed that openSUSE (though I'm sure it has nothing to do with the distro) has different output in /etc/fstab and /boot/grub/menu.lst, more precisely the partition name is for example "/dev/disk/by-id/numbers-brandname-morenumbers-part2" instead of "/dev/sda2" -- but it basically is a simple symlink. My questions about this: what is the point of such symlinks, especially if we're restoring on a different disk? is there a way to cleanly prevent the creation of those symlinks and use the "true" /dev/sdx everywhere instead? if the previous is no, do you know a way to replace those symlinks on the fly in a text file? I tried this script but only works if the file starts with the symlink description (case of fstab, not menu.lst): ### search and replace /dev/disk/by-id/... to /dev/sdx while read oldVolume rest; do # get first element, ignore rest of line if [[ "$oldVolume" =~ ^/dev/disk/by-id/.*(-part[0-9]*$)? ]]; then newVolume=$(readlink $oldVolume) # replace pointer by pointee, returns "../../sdx" echo /dev/${newVolume##*/} $rest >> TMP # format to "/dev/sdx", write line else echo $oldVolume $rest >> TMP # nothing to do fi done < $file mv -f TMP $file # save changes I've had trouble finding a solution to this on google so I was hoping some of the members here could help me. Thank you.

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  • Interesting things – Twitter annotations and your phone as a web server

    - by jamiet
    I overheard/read a couple of things today that really made me, data junkie that I am, take a step back and think, “Hmmm, yeah, that could be really interesting” and I wanted to make a note of them here so that (a) I could bring them to the attention of anyone that happens to read this and (b) I can maybe come back here in a few years and see if either of these have come to fruition. Your phone as a web server While listening to Jon Udell’s (twitter) “Interviews with Innovators Podcast” today in which he interviewed Herbert Van de Sompel (twitter) about his Momento project. During the interview Jon and Herbert made the following remarks: Jon: [some people] really had this vision of a web of servers, the notion that every node on the internet, every connected entity, is potentially a server and a client…we can see where we’re getting to a point where these endpoint devices we have in our pockets are going to be massively capable and it may be in the not too distant future that significant chunks of the web archive will be cached all over the place including on your own machine… Herbert: wasn’t it Opera who at one point turned your browser into a server? That really got my brain ticking. We all carry a mobile phone with us and therefore we all potentially carry a mobile web server with us as well and to my mind the only thing really stopping that from happening is the capabilities of the phone hardware, the capabilities of the network infrastructure and the will to just bloody do it. Certainly all the standards required for addressing a web server on a phone already exist (to this uninitiated observer DNS and IPv6 seem to solve that problem) so why not? I tweeted about the idea and Rory Street answered back with “why would you want a phone to be a web server?”: Its a fair question and one that I would like to try and answer. Mobile phones are increasingly becoming our window onto the world as we use them to upload messages to Twitter, record our location on FourSquare or interact with our friends on Facebook but in each of these cases some other service is acting as our intermediary; to see what I’m thinking you have to go via Twitter, to see where I am you have to go to FourSquare (I’m using ‘I’ liberally, I don’t actually use FourSquare before you ask). Why should this have to be the case? Why can’t that data be decentralised? Why can’t we be masters of our own data universe? If my phone acted as a web server then I could expose all of that information without needing those intermediary services. I see a time when we can pass around URLs such as the following: http://jamiesphone.net/location/current - Where is Jamie right now? http://jamiesphone.net/location/2010-04-21 – Where was Jamie on 21st April 2010? http://jamiesphone.net/thoughts/current – What’s on Jamie’s mind right now? http://jamiesphone.net/blog – What documents is Jamie sharing with me? http://jamiesphone.net/calendar/next7days – Where is Jamie planning to be over the next 7 days? and those URLs get served off of the phone in our pockets. If we govern that data then we can control who has access to it and (crucially) how long its available for. Want to wipe yourself off the face of the web? its pretty easy if you’re in control of all the data – just turn your phone off. None of this exists today but I look forward to a time when it does. Opera really were onto something last June when they announced Opera Unite (admittedly Unite only works because Opera provide an intermediary DNS-alike system – it isn’t totally decentralised). Opening up Twitter annotations Last week Twitter held their first developer conference called Chirp where they announced an upcoming new feature called ‘Twitter Annotations’; in short this will allow us to attach metadata to a Tweet thus enhancing the tweet itself. Think of it as a richer version of hashtags. To think of it another way Twitter are turning their data into a humongous Entity-Attribute-Value or triple-tuple store. That alone has huge implications both for the web and Twitter as a whole – the ability to enrich that 140 characters data and thus make it more useful is indeed compelling however today I stumbled upon a blog post from Eugene Mandel entitled Tweet Annotations – a Way to a Metadata Marketplace? where he proposed the idea of allowing tweets to have metadata added by people other than the person who tweeted the original tweet. This idea really fascinated me especially when I read some of the potential uses that Eugene and his commenters suggested. They included: Amazon could attach an ISBN to a tweet that mentions a book. Specialist clients apps for book lovers could be built up around this metadata. Advertisers could pay to place adverts in metadata. The revenue generated from those adverts could be shared with the tweeter or people who add the metadata. Granted, allowing anyone to add metadata to a tweet has the potential to create a spam problem the like of which we haven’t even envisaged but spam hasn’t halted the growth of the web and neither should it halt the growth of data annotations either. The original tweeter should of course be able to determine who can add metadata and whether it should be moderated. As Eugene says himself: Opening publishing tweet annotations to anyone will open the way to a marketplace of metadata where client developers, data mining companies and advertisers can add new meaning to Twitter and build innovative businesses. What Eugene and his followers did not mention is what I think is potentially the most fascinating use of opening up annotations. Google’s success today is built on their page rank algorithm that measures the validity of a web page by the number of incoming links to it and the page rank of the sites containing those links – its a system built on reputation. Twitter annotations could open up a new paradigm however – let’s call it People rank- where reputation can be measured by the metadata that people choose to apply to links and the websites containing those links. Its not hard to see why Google and Microsoft have paid big bucks to get access to the Twitter firehose! Neither of these features, phones as a web server or the ability to add annotations to other people’s tweets, exist today but I strongly believe that they could dramatically enhance the web as we know it today. I hope to look back on this blog post in a few years in the knowledge that these ideas have been put into place. @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • C# tip: do not use “is” type, if you will need cast “as” later

    - by Michael Freidgeim
    We have a debate with one of my collegues, is it agood style to check, if the object of particular style, and then cast  as this  type. The perfect answer of Jon Skeet   and answers in Cast then check or check then cast? confirmed my point.//good    var coke = cola as CocaCola;    if (coke != null)    {        // some unique coca-cola only code    }    //worse    if (cola is CocaCola)    {        var coke =  cola as CocaCola;        // some unique coca-cola only code here.    }

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