Search Results

Search found 15377 results on 616 pages for 'socket programming'.

Page 257/616 | < Previous Page | 253 254 255 256 257 258 259 260 261 262 263 264  | Next Page >

• How to learn the math behind the code?

  - by Solomon Wise

  I am a 12 year old who has recently gotten into programming. (Although I know that the number of books you have read does not determine your programming competency or ability, just to paint a "map" of where I am in terms of the content I know...) I've finished the books: Python 3 For Absolute Beginners Pro Python Python Standard Library by Example Beautiful Code Agile Web Development With Rails and am about halfway into Programming Ruby. I have written many small programs (One that finds which files have been updated and deleted in a directory, one that compares multiple players' fantasy baseball value, and some text based games, and many more). Obviously, as I'm not some sort of child prodigy, I can't take a formal Computer Science course until high school. I really want to learn computer science to increase my knowledge about the code, and the how the code runs. I've really become interested in the math part after reading the source code for Python's random module. Is there a place where I can learn CS, or programming math online for free, at a level that would be at least partially understandable to a person my age?

  Read the article

• Which toolkit to use for 3D MMO game development?

  - by Ahmet Yildirim

  Lately i've been thinking about which path to follow for developing an 3D Online game. I have googled a lot but i couldnt find a good article that covers both game development and online server & client development in same context. This question has been in mind for about 2 weeks now. So.. yesterday i started developing a game from scratch by using Irrlicht.Net Wrapper to use Socket library of .NET which im already familiar. But i found out .Net wrapper of Irrlicht is not totally finished yet and still have lacks from the original. So i lost all my motives :/. So i thought why not to ask the experts before i run into another dead end... What Game Engine and Networking Library is best way to go for 3D MMO Development? Here is some of my early conclusions: Please let me know the ones im wrong. C++: Best Performance for 3D Graphics. Most Game Engines has native C++ Libraries. Lacks a Solid Socket Library .NETC++ Lacks Intellisense Support. C#: Intellisense Support NET Socket Library Lacks 3D Graphics Performance Lacks a native solid 3D Game Engine

  Read the article

• Ways to break the "Syndrome of the perfect programmer"

  - by Rushino

  I am probably not the only one that feel that way. But I have what I tend to call "The syndrome of the perfect programmer" which many might say is the same as being perfectionist but in this case it's in the domain of programming. However, the domain of programming is a bit problematic for such a syndrome. Have you ever felt that when you are programming you're not confident or never confident enought that your code is clean and good code that follows most of the best practices ? There so many rules to follow that I feel like being overwhelmed somehow. Not that I don't like to follow the rules of course I am a programmer and I love programming, I see this as an art and I must follow the rules. But I love it too, I mean I want and I love to follow the rules in order to have a good feeling of what im doing is going the right way.. but I only wish I could have everything a bit more in "control" regarding best practices and good code. Maybe it's a lack of organization? Maybe it's a lack of experience? Maybe a lack of practice? Maybe it's a lack of something else someone could point out? Is there any way to get rid of that syndrome somehow ?

  Read the article

• Looking for suggestions: becoming a hireable, young programmer [closed]

  - by Dan

  I am a 17 year old Java programmer that has filled the last year with learning all of the ins and outs of Java - Using Eclipse, and the help of a friend of the family (a Java programming architect for some company), I have learned everything from serializing objects, basic networking, generics, reflection, multi-threading, code optimization and efficiency & some concurrency safety - built my own proxy class, and nowadays, I answer questions on Project Euler. I am seeking some suggestions though on where I go next, or where I go from here to get a job in programming. I dedicate at least an hour every day to coding, sometimes literally, the entire day, and I really have come to love the process. I just started reading Effective Java (v2), and learning Scala (as I see often, possibly the Java replacement) I will be going to college for Computer Science next year - and taking AP computer science this year (however, I took a practice exam and got an 87, only need a 60to70 to pass, so no need to study for it too much) -- I was wondering if getting the SE 7 OCA and OCP would help me in trying to get a programming job. I looked around and most people have said online that an OCA/OCP are practically useless, but, at my age do they make me any more credible? More or less, what would you recommend to get a job in programming these days - or distinguish yourself from the crowd? I have enough time and dedication to learn another language, or anything really. Thank you very much.

  Read the article

• where to start and lack of motivation

  - by anoguy

  I have a few questions that have been bothering me for quite a while, maybe you guys can give me some tips. So let me give a very brief explanation about what I am doing at the moment (like someone cares lol). At the moment I am a last year student on computer science. And like most of you already know is that you won't learn deep programming there, you need to learn it yourself. So at the moment I know like the basics of c++, java, html, php. But it's all bits of this and bits of that. I seriously want to dive deeper in the programming world but there are so many programming languages on the web and there is so much information that i don't know where to start any more.. And that's not the biggest issue, I also lost a bit of my motivation for programming and I like to get more motivation for it so that I love what I do (I am also a very lazy person btw, that's also a problem playing here). So can you guys give me some tips for helping me, because I really want to get pumped up and make cool stuff. (sry for my bad english XD)

  Read the article

• Pros and Cons between learning to program on Windows and Linux and Macs

  - by Amumu

  I have been studying IT for 2 years and I'm going to graduate soon in this year (if everything goes well). I think it's time for me to choose a path to specialized into some fields of this large industry. Personally, I want to be a game programmer. But to be a game programmer, surely I have to invest my time to study Windows Programming, then DirectX and other programming techniques related to game. On the other hand, Linux seems promising as well. I am not sure about Game Programming on for it, but it seems become an expert for this OS, and by expert it's not about using the OS to become an administrator, but can do further than that, such as understand the OS to its essence and can produce applications for it. However, there's some obstacles in my view for this development path. Many of my friends think that Linux is based on free and open source, and if you follow it, as its name suggested: Free and Open Source, it means we also give away our software free. Otherwise, we will have to find a second job to make living. Currently, I think a viable way to make money on Linux is doing works related to client-server. Another way to developer my career is to become expert in developing business applications for companies. This is more on business, not on specialized IT fields so I am not really interested. Another alternative is programming on mobile devices, such as iPhone, Android and it seems very promising and easier to approach. Another way is to become a computer scientist and research on academic subjects such as AI, human-computer interaction, but this is far beyond my reach, so I won't invest my time on it until I feel I am experienced enough. That's all I can think of for now. I may miss a lot of things, so I need more opinions as input to get the big picture of the industry for my career path.

  Read the article

• How do you make people accept code review?

  - by user7197

  All programmers have their style of programming. But some of the styles are let’s say... let’s not say. So you have code review to try to impose certain rules for good design and good programming techniques. But most of the programmers don’t like code review. They don’t like other people criticizing their work. Who do they think they are to consider themselves better than me and tell me that this is bad design, this could be done in another way. It works right? What is the problem? This is something they might say (or think but not say which is just as bad if not worse). So how do you make people accept code review without starting a war? How can you convince them this is a good thing; that will only improve their programming skills and avoid a lot of work later to fix and patch a zillion times a thing that hey... "it works"? People will tell you how to make code review (peer-programming, formal inspections etc) what to look for in a code review, studies have been made to show the number of defects that can be discovered before the software hits production etc. But how do you convince programmers to accept a code review?

  Read the article

• How would you react if someone told you your code is a mess?

  - by newbie

  I am a good programmer, or so I thought before. I always love to program. And I want to learn many things about programming to make me a better programmer. I studied programming for 1 year and now I am working as a programmer for almost 2 years. So in short, I have almost 3 years programming experience. Our team is composed of 5 programmers, and 4 of us are new, 1 has more than 3 year experience. We've been working for a program for almost a year now and nobody ever review my code and I was given a page to work with. We never had a code review and we are all new so we don't know what is a clean code looks like. I think programmers learn by themselves? We deployed our program to the program without thorough testing. Now it is tight and we need an approval and code review first before we make changes with the code. For the first time, someone reviews my code and he says it is a mess. I feel so sad and hurt. I really love programming and making them say something like that really hurts me. I really want to improve myself. But it seems like I'm not a genius programmer like in the movies. Can you give me advise on how to be better? Have you ever experience something criticizing your code and you feel really hurt? What do you do on those events.. Thank you

  Read the article

• Java and what to do with it

  - by SterAllures

  I've been browsing through several websites and several topics on this website. Now I'm just a starting programmer and I want to make a good decision. From what I understand is that Java is used alot for server stuff, and web applets but not really for computer applications running on a client, it's also used for Android programming and several other mobiles. I'm really interested in Android programming, I really love to program for mobile devices, in this case Android because I really think it has a lot of potential and I don't like the iPhone. If I want to program on Android I have to learn Java (aside from Mono). but if my decision changes over the next couple of years I don't think Java is the right language to get a job that programs computer applications. I think I get a job where I have to program server stuff, rather than computer applications. That's why I think C# is a good choice. I can program for Windows Phone 7 (I hope that will get big). and I have the feeling C# is more widely used for computer applications. so I think C# is more versatile looking at Mobile programming and computer programming. Or am I totally wrong thinking this?

  Read the article

• When is the right time to join open source project for programmer?

  - by Mahesh

  Most of the newcomers in programming start with basic projects to start with programming. Most of the C++ progammers spend some time with puzzles and contests but this is not always helpful. Sometimes you've to spend some time on real projects. Starting your own open source project could be a problem in self-learning for newbie cause of lack of mentors and peers who can't look at your code and give suggestions. Open source projects can solve this problem, some projects could be best suited for new programmers. Besides everybody is newbie at some point. So i'll try and make this question a bit from beginners perspective. I tried few questions on stack overflow before asking this like How do i join & Bare minimum you need and how to get involved with open source and what level of programming etc. But this is not helping me when it comes to self-evaluating with skills. How to find that out ? How can i check what it takes to join open source project and am i really that comfortable with huge source code etc. My question is when to consider yourself comfortable joining open source programming ? I mean how will you test yourself that you're ready to take burden of big/small projects of open source ? how will you test yourself to see if you could work with version control/other programmers/tight schedule etc ?

  Read the article

• I am not the most logically-organized person. Do I have any chance at being a good 'low-level' programmer?

  - by user217902

  Background: I am entering college next year. I really enjoy making stuff and solving logical problems, so I'm thinking of majoring in compsci and working in software development. I hope to have the kind of job where I can work with implementing / improving algorithms and data structures on a regular basis.. as opposed to, say, a job that's purely concerned with mashing different libraries together, or 'finding the right APIs for the job'. (Hence the word 'low-level' in the title. No, I don't wish to write assembly all day.) Thing is, I've never been the most logically-sharp person. Thus far I have only worked on hobby projects, but I find that I make the silliest of errors ever so often, and it can take me ages to find it. Like anywhere between three hours to a day to locate a simple segfault, off-by-one error, or other logical mistake. (Of course, I do other things in the meantime, like browsing SO, reddit, and the like..) It's not like I'm 'new' to programming either; I first tried C++ maybe five years ago. My question is: is this normal? Should a programmer with any talent solve it in less time? Having read Spolsky's Smart and gets things done, where he talks about the large variance in programming speed, am I near the bottom of the curve, and therefore destined to work in companies that cannot afford to hire quality programmers? I'd like to think that conceptually I'm okay -- I can grasp algorithms and concepts pretty well, I do fine in math and science, although I probably drop signs in my equations more often than the next guy. Still, grokking concepts makes me happy, and is the reason why I want to work with algorithms. I'm hoping to hear from those of you with real-world programming experience. TL;DR: I make many careless mistakes, should I not consider programming as a career?

  Read the article

• c# vocabulary

  - by foxjazz

  I have probably seen and used the word Encapsulation 4 times in my 20 years of programming.I now know what it is again, after an interview for a c# job. Even though I have used the public, private, and protected key words in classes for as long as c# was invented. I can sill remember coming across the string.IndexOf function and thinking, why didn't they call it IndexAt.Now with all the new items like Lambda and Rx, Linq, map and pmap etc, etc. I think the more choices there is to do 1 or 2 things 10 or 15 differing ways, the more programmers think to stay with what works and try and leverage the new stuff only when it really becomes beneficial.For many, the new stuff is harder to read, because programmers aren't use to seeing declarative notation.I mean I have probably used yield break, twice in my project where it may have been possible to use it many more times. Or the using statement ( not the declaration of namespace references) but inline using. I never really saw a big advantage to this, other than confusion. It is another form of local encapsulation (oh there 5 times used in my programming career) but who's counting?  THE COMPUTERS ARE COUNTING!In business logic most programming is about displaying lists, selecting items in a list, and sending those choices to some other system or database to keep track of those selections. What makes this difficult is how these items relate to one, each other, and two externally listed items.Well I probably need to go back to school and learn c# certification so I can say I am an expert in c#. Apparently using all aspects of c# (even unsafe code) in my programming life, doesn't make me certified, just certifiable.This is a good time to sign off:Fox-jazzy

  Read the article

• Limiting my heavy thinking to my job [closed]

  - by Robin Castlin

  This might be a weird problem which is only to a half relevant to actual programming, but hopefully there are people here that knows what I'm talking about. Basicly I'm proud of how I can deal with coding problems and fix them in short notice and many other aspects like building new systems and such. I'm fast on finding solutions and I often think about the impact my changes does to existing systems and so on, therefor preventing problem from arising at all and such. I am simply happy with how my mind operates when it comes to programming and I wouldn't want to change it at all. The problem, however is when I'm not programming. I find myself rather limited in social situations. I can't determine if it is through programming, but I sometimes think way to much about the consequences when it comes to being social. I know from own experience that most times you earn by not thinking about consequences, but it's hard for me not to. Often my friends tells me "I think too much" and even though I agree, I can't seem to change this behavior. My brain wants to think, and it likes to overthink simple stuff. Does anyone recognize the bad habit of not leaving advanced thinking at work, and in what way do you deal with it? If this isn't a suitable place to ask this question, I apologize and hope you may point me to the right site.

  Read the article

• Please recommend the best tools to build a test plan management tool

  - by fzkl

  I have mostly worked on hardware testing in my professional career and would like to get onto the software development side. I thought working on a practically usable project will help motivate me and help acquire some skills. I have decided to build a test plan management tool for the QA team I work in (We use excel sheets!). The test plan management tool should be browser based and should support this: There would be many test plans, each test plan having test sets, test sets having test cases and test cases having instructions, attachments and Pass/fail status marking and bug info in case of failure. It should also have an export to excel option. I have a visual picture of the tool I am looking to build but I don't have enough experience to figure our where to start. My current programming skills are limited to C and shell programming and I want to pick up python. What tools (programming language, database and anything else?) would you recommend for me to get this done? Also what are the key concepts in the recommended programming language that I should focus on to build a browser based tool like this?

  Read the article

• Need Directions to become a programmer [closed]

  - by Omin

  Before youguys go on about how there are many types of programmers, please read through the post. Long term goal: Develop my own software (company) Short term goal: Get a job that involves coding/programming Current status: Support Analyst (at a software company but does not involve any programming) with 40k salary, 3rd year computer engineering student I had everything figured out. I'm going to develop a 2D scrolling game for iphone or android, publish the app, sell a bunch, and then apply at a studios as a software developer. And then something hit me. I think I need to get a job that involes programming to learn as much as I can in the shortest time possible. So I got a phone interview at a fast growing start up software company, passed that no problem, but then had to take an online technical assessment. That failed miserably. I thought that if I could just present myself, show that I am hard working, positive attitude, eager to make self improvements, type of a guy, I could get the job. I was wrong. And now, I am lost. Im thinking of staying with my job until I find a new one as a programmer. I will be working, self studying, and trying to make this happen without finishing university. I forgot to mention that the online technical assessment was based on data structures/algorithms, OO design, runtime complexity. I was hoping that I could get some guidence. Should I be focusing on app development or study computer science fundamentals? I have a list of books I can be going through: Learning C# O'Reilly (I got interested in C# because of Unity3D and Mono), C# 5.0 in a Nutshell, Head First Design Patterns, Code Complete, Introduction to Algorithms, Programming Interviews Exposed, Cracking the Coding Interview, The Google Resume.

  Read the article

• Information I need to know as a Java Developer [on hold]

  - by Woy

  I'm a java developer. I'm trying to get more knowledge to become a better programmer. I've listed a number of technologies to learn. Instead of what I've listed, what technologies would you suggest to learn as well for a Junior Java Developer? I realize, there's a lot of things to study. Java: - how a garbage collector works - resource management - network programming - TCP/IP HTTP - transactions, - consistency: interfaces, classes collections, hash codes, algorithms, comp. complexity concurrent programming: synchronizing, semafores steam management metability: thread-safety byte code manipulations, reflections, Aspect-Oriented Programming as base to understand frameworks such as Spring etc. Web stack: servlets, filters, socket programming Libraries: JDK, GWT, Apache Commons, Joda-Time, Dependency Injections: Spring, Nano Tools: IDE: very good knowledge - debugger - profiler - web analyzers: Wireshark, firebugs - unit testing SQL/Databases: Basics SELECTing columns from a table Aggregates Part 1: COUNT, SUM, MAX/MIN Aggregates Part 2: DISTINCT, GROUP BY, HAVING + Intermediate JOINs, ANSI-89 and ANSI-92 syntax + UNION vs UNION ALL x NULL handling: COALESCE & Native NULL handling Subqueries: IN, EXISTS, and inline views Subqueries: Correlated ITH syntax: Subquery Factoring/CTE Views Advanced Topics Functions, Stored Procedures, Packages Pivoting data: CASE & PIVOT syntax Hierarchical Queries Cursors: Implicit and Explicit Triggers Dynamic SQL Materialized Views Query Optimization: Indexes Query Optimization: Explain Plans Query Optimization: Profiling Data Modelling: Normal Forms, 1 through 3 Data Modelling: Primary & Foreign Keys Data Modelling: Table Constraints Data Modelling: Link/Corrollary Tables Full Text Searching XML Isolation Levels Entity Relationship Diagrams (ERDs), Logical and Physical Transactions: COMMIT, ROLLBACK, Error Handling

  Read the article

• How to progress far enough in a year [on hold]

  - by xCasper

  So I came to a realization the other day, I graduate in a year. I will have completed my four year degree in about two and a half (I went to a school that goes full time year round). Anyway, I want to get a job, as a programmer, when I graduate. The problem is, I feel like I am no where near ready. In the last year I cant say I have made any spectacular projects. I know that my advanced programming courses are coming up, but by the time I take them, I will be graduating in 6 months. Not nearly enough time to really take what I learn, apply it, and create something to show for myself. I want to push myself ahead of the game; mainly because my major is Computer Information Systems, so the focus is not programming. In fact, I only get, 4 programming classes. Before anyone says anything, CIS is the closest to a programming major at my school that I am able to do. So the questions come down to this: 1) What can I do to really step up the speed at which I progress (on my own) 2) Should I be aiming for a certain amount of projects in my "Portfolio." 2a) Should they be big projects? P.S: The language we have used in school in c++, I do take a Java class in the spring, and .net over Summer; if any of that matters for anything.

  Read the article

• Telnet connection using c#

  - by alejandrobog

  Our office currently uses telnet to query an external server. The procedure is something like this. Connect - telnet opent 128........ 25000 Query - we paste the query and then hit alt + 019 Response - We receive the response as text in the telnet window So I’m trying to make this queries automatic using a c# app. My code is the following First the connection. (No exceptions) SocketClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); String szIPSelected = txtIPAddress.Text; String szPort = txtPort.Text; int alPort = System.Convert.ToInt16(szPort, 10); System.Net.IPAddress remoteIPAddress = System.Net.IPAddress.Parse(szIPSelected); System.Net.IPEndPoint remoteEndPoint = new System.Net.IPEndPoint(remoteIPAddress, alPort); SocketClient.Connect(remoteEndPoint); Then I send the query (No exceptions) string data ="some query"; byte[] byData = System.Text.Encoding.ASCII.GetBytes(data); SocketClient.Send(byData); Then I try to receive the response byte[] buffer = new byte[10]; Receive(SocketClient, buffer, 0, buffer.Length, 10000); string str = Encoding.ASCII.GetString(buffer, 0, buffer.Length); txtDataRx.Text = str; public static void Receive(Socket socket, byte[] buffer, int offset, int size, int timeout) { int startTickCount = Environment.TickCount; int received = 0; // how many bytes is already received do { if (Environment.TickCount > startTickCount + timeout) throw new Exception("Timeout."); try { received += socket.Receive(buffer, offset + received, size - received, SocketFlags.None); } catch (SocketException ex) { if (ex.SocketErrorCode == SocketError.WouldBlock || ex.SocketErrorCode == SocketError.IOPending || ex.SocketErrorCode == SocketError.NoBufferSpaceAvailable) { // socket buffer is probably empty, wait and try again Thread.Sleep(30); } else throw ex; // any serious error occurr } } while (received < size); } Every time I try to receive the response I get "an exsiting connetion has forcibly closed by the remote host" if open telnet and send the same query I get a response right away Any ideas, or suggestions?

  Read the article

• Java multithreaded server - each connection returns data. Processing on main thread?

  - by oliwr

  I am writing a client with an integrated server that should wait indefinitely for new connections - and handle each on a Thread. I want to process the received byte array in a system wide available message handler on the main thread. However, currently the processing is obviously done on the client thread. I've looked at Futures, submit() of ExecutorService, but as I create my Client-Connections within the Server, the data would be returned to the Server thread. How can I return it from there onto the main thread (in a synchronized packet store maybe?) to process it without blocking the server? My current implementation looks like this: public class Server extends Thread { private int port; private ExecutorService threadPool; public Server(int port) { this.port = port; // 50 simultaneous connections threadPool = Executors.newFixedThreadPool(50); } public void run() { try{ ServerSocket listener = new ServerSocket(this.port); System.out.println("Listening on Port " + this.port); Socket connection; while(true){ try { connection = listener.accept(); System.out.println("Accepted client " + connection.getInetAddress()); connection.setSoTimeout(4000); ClientHandler conn_c= new ClientHandler(connection); threadPool.execute(conn_c); } catch (IOException e) { System.out.println("IOException on connection: " + e); } } } catch (IOException e) { System.out.println("IOException on socket listen: " + e); e.printStackTrace(); threadPool.shutdown(); } } } class ClientHandler implements Runnable { private Socket connection; ClientHandler(Socket connection) { this.connection=connection; } @Override public void run() { try { // Read data from the InputStream, buffered int count; byte[] buffer = new byte[8192]; InputStream is = connection.getInputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream(); // While there is data in the stream, read it while ((count = is.read(buffer)) > 0) { out.write(buffer, 0, count); } is.close(); out.close(); System.out.println("Disconnect client " + connection.getInetAddress()); connection.close(); // handle the received data MessageHandler.handle(out.toByteArray()); } catch (IOException e) { System.out.println("IOException on socket read: " + e); e.printStackTrace(); } return; } }

  Read the article

• Abnormally disconnected TCP sockets and write timeout

  - by James

  Hello I will try to explain the problem in shortest possible words. I am using c++ builder 2010. I am using TIdTCPServer and sending voice packets to a list of connected clients. Everything works ok untill any client is disconnected abnormally, For example power failure etc. I can reproduce similar disconnect by cutting the ethernet connection of a connected client. So now we have a disconnected socket but as you know it is not yet detected at server side so server will continue to try to send data to that client too. But when server try to write data to that disconnected client ...... Write() or WriteLn() HANGS there in trying to write, It is like it is wating for somekind of Write timeout. This hangs the hole packet distribution process as a result creating a lag in data transmission to all other clients. After few seconds "Socket Connection Closed" Exception is raised and data flow continues. Here is the code try { EnterCriticalSection(&SlotListenersCriticalSection); for(int i=0;i<SlotListeners->Count;i++) { try { //Here the process will HANG for several seconds on a disconnected socket ((TIdContext*) SlotListeners->Objects[i])->Connection->IOHandler->WriteLn("Some DATA"); }catch(Exception &e) { SlotListeners->Delete(i); } } }__finally { LeaveCriticalSection(&SlotListenersCriticalSection); } Ok i already have a keep alive mechanism which disconnect the socket after n seconds of inactivity. But as you can imagine, still this mechnism cant sync exactly with this braodcasting loop because this braodcasting loop is running almost all the time. So is there any Write timeouts i can specify may be through iohandler or something ? I have seen many many threads about "Detecting disconnected tcp socket" but my problem is little different, i need to avoid that hangup for few seconds during the write attempt. So is there any solution ? Or should i consider using some different mechanism for such data broadcasting for example the broadcasting loop put the data packet in some kind of FIFO buffer and client threads continuously check for available data and pick and deliver it to themselves ? This way if one thread hangs it will not stop/delay the over all distribution thread. Any ideas please ? Thanks for your time and help. Regards Jams

  Read the article

• How to create a simple Proxy to access web servers in C

  - by jesusiniesta

  Hi. I’m trying to create an small Web Proxy in C. First, I’m trying to get a webpage, sending a GET frame to the server. I don’t know what I have missed, but I am not receiving any response. I would really appreciate if you can help me to find what is missing in this code. int main (int argc, char** argv) { int cache_size, //size of the cache in KiB port, port_google = 80, dir, mySocket, socket_google; char google[] = "www.google.es", ip[16]; struct sockaddr_in socketAddr; char buffer[10000000]; if (GetParameters(argc,argv,&cache_size,&port) != 0) return -1; GetIP (google, ip); printf("ip2 = %s\n",ip); dir = inet_addr (ip); printf("ip3 = %i\n",dir); /* Creation of a socket with Google */ socket_google = conectClient (port_google, dir, &socketAddr); if (socket_google < 0) return -1; else printf("Socket created\n"); sprintf(buffer,"GET /index.html HTTP/1.1\r\n\r\n"); if (write(socket_google, (void*)buffer, LONGITUD_MSJ+1) < 0 ) return 1; else printf("GET frame sent\n"); strcpy(buffer,"\n"); read(socket_google, buffer, sizeof(buffer)); // strcpy(message,buffer); printf("%s\n", buffer); return 0; } And this is the code I use to create the socket. I think this part is OK, but I copy it just in case. int conectClient (int puerto, int direccion, struct sockaddr_in *socketAddr) { int mySocket; char error[1000]; if ( (mySocket = socket(AF_INET, SOCK_STREAM, 0)) == -1) { printf("Error when creating the socket\n"); return -2; } socketAddr->sin_family = AF_INET; socketAddr->sin_addr.s_addr = direccion; socketAddr->sin_port = htons(puerto); if (connect (mySocket, (struct sockaddr *)socketAddr,sizeof (*socketAddr)) == -1) { snprintf(error, sizeof(error), "Error in %s:%d\n", __FILE__, __LINE__); perror(error); printf("%s\n",error); printf ("-- Error when stablishing a connection\n"); return -1; } return mySocket; } Thanks!

  Read the article

• Javascript: Writing a firefox extension with sockets

  - by Johnny Grass

  I need to write a firefox extension that creates a server socket (I think that's what it's called) and returns the browser's current url when a client application (running on the same computer) sends it a request. The thing is that I have no Java/Javascript background at all and I'm pressed for time so I am trying to hack something together from code samples. So far I've been mildly successful. I've been working with code from this question which is used in the open source Firefox exension PolyChrome I have the following code: var reader = { onInputStreamReady : function(input) { var input_stream = Components.classes["@mozilla.org/scriptableinputstream;1"] .createInstance(Components.interfaces.nsIScriptableInputStream); input_stream.init(input); input_stream.available(); var request = ''; while (input_stream.available()) { request = request + input_stream.read(512); } var checkString = "foo" if (request.toString() == checkString.toString()) { output_console('URL: ' + content.location.href); } else output_console("nothing"); var thread_manager = Components.classes["@mozilla.org/thread-manager;1"].getService(); input.asyncWait(reader,0,0,thread_manager.mainThread); } } var listener = { onSocketAccepted: function(serverSocket, clientSocket) { output_console("Accepted connection on "+clientSocket.host+":"+clientSocket.port); input = clientSocket.openInputStream(0, 0, 0).QueryInterface(Components.interfaces.nsIAsyncInputStream); output = clientSocket.openOutputStream(Components.interfaces.nsITransport.OPEN_BLOCKING, 0, 0); var thread_manager = Components.classes["@mozilla.org/thread-manager;1"].getService(); input.asyncWait(reader,0,0,thread_manager.mainThread); } } var serverSocket = Components.classes["@mozilla.org/network/server-socket;1"]. createInstance(Components.interfaces.nsIServerSocket); serverSocket.init(9999, true, 5); output_console("Opened socket on " + serverSocket.port); serverSocket.asyncListen(listener); I have a few questions. So far I can telnet into localhost and get a response, but my string comparison in the reader seems to fail even if I enter "foo". I don't get why. What am I missing? The sample code I'm using opens up a console window and prints output when I telnet into localhost. Ideally I would like the output to be returned as a response when the client sends a request to the server socket with a passphrase. How do I go about doing that? Is doing this a good idea? Does it create security vulnerabilities on the computer? How can I block connections to the socket from other computers? What is a good place to read about javascript sockets? My google searches have been pretty fruitless but then maybe I'm not using the right keywords.

  Read the article

• Router Alert options on IGMPv2 packets

  - by Scakko

  I'm trying to forge an IGMPv2 Membership Request packet and send it on a RAW socket. The RFC 3376 states: IGMP messages are encapsulated in IPv4 datagrams, with an IP protocol number of 2. Every IGMP message described in this document is sent with an IP Time-to-Live of 1, IP Precedence of Internetwork Control (e.g., Type of Service 0xc0), and carries an IP Router Alert option [RFC-2113] in its IP header So the IP_ROUTER_ALERT flag must be set. I'm trying to forge the strict necessary of the packet (e.g. only the IGMP header & payload), so i'm using the setsockopt to edit the IP options. some useful variables: #define C_IP_MULTICAST_TTL 1 #define C_IP_ROUTER_ALERT 1 int sockfd = 0; int ecsockopt = 0; int bytes_num = 0; int ip_multicast_ttl = C_IP_MULTICAST_TTL; int ip_router_alert = C_IP_ROUTER_ALERT; Here's how I open the RAW socket: sock_domain = AF_INET; sock_type = SOCK_RAW; sock_proto = IPPROTO_IGMP; if ((ecsockopt = socket(sock_domain,sock_type,sock_proto)) < 0) { printf("Error %d: Can't open socket.\n", errno); return 1; } else { printf("** Socket opened.\n"); } sockfd = ecsockopt; Then I set the TTL and Router Alert option: // Set the sent packets TTL if((ecsockopt = setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, &ip_multicast_ttl, sizeof(ip_multicast_ttl))) < 0) { printf("Error %d: Can't set TTL.\n", ecsockopt); return 1; } else { printf("** TTL set.\n"); } // Set the Router Alert if((ecsockopt = setsockopt(sockfd, IPPROTO_IP, IP_ROUTER_ALERT, &ip_router_alert, sizeof(ip_router_alert))) < 0) { printf("Error %d: Can't set Router Alert.\n", ecsockopt); return 1; } else { printf("** Router Alert set.\n"); } The setsockopt of IP_ROUTER_ALERT returns 0. After forging the packet, i send it with sendto in this way: // Send the packet if((bytes_num = sendto(sockfd, packet, packet_size, 0, (struct sockaddr*) &mgroup1_addr, sizeof(mgroup1_addr))) < 0) { printf("Error %d: Can't send Membership report message.\n", bytes_num); return 1; } else { printf("** Membership report message sent. (bytes=%d)\n",bytes_num); } The packet is sent, but the IP_ROUTER_ALERT option (checked with wireshark) is missing. Am i doing something wrong? is there some other methods to set the IP_ROUTER_ALERT option? Thanks in advance.

  Read the article

• How can I obtain the IP address of my server program?

  - by Dr Dork

  Hello! This question is related to another question I just posted. I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code and client side code setup to communicate. Currently, my client code successfully connects to the server code and the server code sends it a test message, then both quit out. Perfect! That's exactly what I wanted to accomplish. Now I'm playing around with the functions used to obtain info about the two environments (server and client). I'd like to obtain my server program's IP address. Here's the code I currently have to do this, but it's not working... int sockfd; unsigned int len; socklen_t sin_size; char msg[]="test message"; char buf[MAXLEN]; int st, rv; struct addrinfo hints, *serverinfo, *p; struct sockaddr_storage client; char s[INET6_ADDRSTRLEN]; char ip[INET6_ADDRSTRLEN]; //zero struct memset(&hints,0,sizeof(hints)); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_PASSIVE; //get the server info if((rv = getaddrinfo(NULL, SERVERPORT, &hints, &serverinfo ) != 0)){ perror("getaddrinfo"); exit(-1); } // loop through all the results and bind to the first we can for( p = serverinfo; p != NULL; p = p->ai_next) { //Setup the socket if( (sockfd = socket( p->ai_family, p->ai_socktype, p->ai_protocol )) == -1 ) { perror("socket"); continue; } //Associate a socket id with an address to which other processes can connect if(bind(sockfd, p->ai_addr, p->ai_addrlen) == -1){ close(sockfd); perror("bind"); continue; } break; } if( p == NULL ){ perror("Fail to bind"); } inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr), s, sizeof(s)); printf("Server has TCP Port %s and IP Address %s\n", SERVERPORT, s); and the output for the IP is always empty... server has TCP Port 21412 and IP Address :: any ideas for what I'm missing? thanks in advance for your help! this stuff is really complicated at first.

  Read the article

• how to create multiple tcp connections between server and client

  - by lowcosthighperformance

  I am new in Unix/Linux networking programming, so I have written server-client program in below.In this code there is one socket between client and server, client requests to server, then server responses from 1 to 100 numbers to client. So my question is how can we do this process with 3 socket( tcp connection) without using thread? ( e.g. First socket runs then second runs then third runs then first again .. ) Do you have any suggestion? Thank you client.c int main() { int sock; struct sockaddr_in sa; int ret; char buf[1024]; int x; sock = socket (AF_INET, SOCK_STREAM, 0); bzero (&sa, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_port = htons(SERVER_PORT); inet_pton (AF_INET, SERVER_IP, &sa.sin_addr); ret = connect (sock, (const struct sockaddr *) &sa,sizeof (sa)); if (ret != 0) { printf ("connect failed\n"); exit (0); } x = 0; while (x != -1) { read (sock, buf , sizeof(int)); x = ntohl(*((int *)buf)); if (x != -1) printf ("int rcvd = %d\n", x); } close (sock); exit (0); } server.c int main() { int list_sock; int conn_sock; struct sockaddr_in sa, ca; socklen_t ca_len; char buf[1024]; int i; char ipaddrstr[IPSTRLEN]; list_sock = socket (AF_INET, SOCK_STREAM, 0); bzero (&sa, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_addr.s_addr = htonl(INADDR_ANY); sa.sin_port = htons(SERVER_PORT); bind (list_sock,(struct sockaddr *) &sa,sizeof(sa)); listen (list_sock, 5); while (1){ bzero (&ca, sizeof(ca)); ca_len = sizeof(ca); // important to initialize conn_sock = accept (list_sock,(struct sockaddr *) &ca,&ca_len); printf ("connection from: ip=%s port=%d \n",inet_ntop(AF_INET, &(ca.sin_addr), ipaddrstr, IPSTRLEN),ntohs(ca.sin_port)); for (i=0; i<100; ++i){ *((int *)buf) = htonl(i+20); // we using converting to network byte order write (conn_sock, buf, sizeof(int)); } * ((int *)buf) = htonl(-1); write (conn_sock, buf, sizeof(int)); close (conn_sock); printf ("server closed connection to client\n"); } }

  Read the article

< Previous Page | 253 254 255 256 257 258 259 260 261 262 263 264  | Next Page >