I have a c++ project (server-side) which sends the data to the client side with the help of event source. Now for debugging purposes I have maintained a trace file (text). On all the critical areas in the c++ code where there is a fear of code-break, I have added a line which writes the "success" text to this trace file. It works fine. I can know where the code is success and where it failed.
But I am on the server side. I want to avail this facility to the client too. However, I am unsure about how to do that? Should I stream the file on web-browser, or is there any other way I can send the data "live" to web-browser?
I checked this link, however, I am not sure if I can use this. http://www.tutorialspoint.com/cplusplus/cpp_web_programming.htm
Thanks
your question is a bit confusing, and without any sample of your code it is a bit unclear of what you want to do. however, the best suggestion i can give is to do this:
Store the text document on a server of your choice.
write a program to contact the server and download the data. (Using Winsock.h)
OR
Directly send the file to the computer. you'll have to write a program to contact the server at which point B is located.
for information on writing an application using Winsock.h, check here:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms737629(v=vs.85).aspx
if you really must store the data live in a web browser, then take a look at Java or VisualBasic, as both are heavily supported in all web browsers, while C++ is not.
Let me see if I understand you correctly. You want to send success / failure of the webserver to your client program?
Well, that's part of the job of a webserver, as dictated by the http protocol. A webserver will respond to a client request with a response header, followed by the requested page (if it exists as a valid resource on the server).
For more information on http response headers have a look at this article, or this wikipedia page, which both detail the request / response conversation between browser and webserver.
Hope this helps.
Related
I'm using the following line to download a file, and when I do that, it's not downloading the most recent file.
HRESULT hr = URLDownloadToFile(NULL, _T("http://example.com/users.txt"), _T("users.txt"), 0, NULL);
On the first run, users.txt has 3 names in it, if you were to remove a name, and run it again it still downloads with 3 names.
I'm using remove("users.txt); to remove the file prior to download.
It is probably operating system specific, or at least you need a library for HTTP client side.
You need to read a lot more about the HTTP protocol. The formulation of your question makes me believe you don't understand much about it.
On some OSes (notably Linux and POSIX compliant ones), you can use libcurl (which is a good HTTP client free software library)
URLDownloadToFile seems to be a Windows specific thing. Did you carefully read its documentation? It is returning some error code. Do you handle hr correctly?
You can probably only get what the HTTP protocol (response from web server, for a GET HTTP request) gives you. Mostly, the MIME type of the content of the URL, the content size, and the content bytes (etc... including content encoding etc...). The fact that the content has 3 names is your understanding of it.
Try to read more about the HTTP protocol, and understand what is really going on. Are any cookies or sessions involved? Did you try to use something like telnet to manually make the HTTP exchange? Are you able to show it and understand it? What it the HTTP response code ?
If you have access to the server (e.g. using ssh) and are able to look into the log files, try to understand what exchanges happened and what HTTP status -i.e. error code- was sent back. Perhaps set up some Linux box locally for initial tests. Or setup some HTTP server locally and use http://localhost/ etc...
I am working on an application that, among other applications, allows users to send emails. It works by writing everything onto an SQL server, so you can have multiple instances of an application.
The email sending currently works with an "Outbox" table on the SQL server, to which application instances directly write the data with SQL statements. I have, however, hit an issue, that a requirement for attachments on the emails has arisen.
My thinking is that if I can send the attached files to a directory on which the SQL server resides (possibly the TEMP directory?), and then store the path to that file (or a UUID, if the file is constant) in the table. The issue is I have no idea particularly where to start with sending the file, as I am still vaguely new to C++.
One term I have come across is sending it with sockets, but am struggling with where to start with it and do not know if it is indeed the best option. Could anyone provide some advice on this matter?
Thanks in advance.
If I correctly understand the way it works (applications save the emails to SQL then another application takes them out and sends them) you have two choices:
Save the attachment as binary in the SQL and have the mailer application do the rest.
Use sockets to transfer the file to the SQL server and save the path to it just as you said.
I'd say option 1 would be the best option if I understood correctly the way its currently working. And as for option 2, there are probably other ways to transfer the file but sockets would be the easily cross-platform option.
Its not hard to get started with sockets, there are a lot of examples all over the internet.
winsock
more winsock
sys/socket.h
more sys/socket.h
Please tell me is it possile to know when a program is trying to download a file ( like in Internet Download Manager ). I want to catch that event (hook it), get the download url, and then destroy the event.
Thanks in advance..
#Jerry Coffin:Sr, I forgot to tell you that this feature of IDM is not active by default. It is only turned on when you enable the "Use advance browser integration" option at "Download/Options" of IDM menu.
Like here :
http://files.myopera.com/UenX/files/Detect.jpg
+ Check the (1) options, OK, then reboot.
+ After reboot, the (2) option will appear, check it, OK, and now run your software. You should see some thing likes (3)
( this appear when I run the msgr9us.exe ( Yahoo! Messenger setup file) )
Give it a try..
For a specific program such as Internet Explorer, doing this is quite reasonable (IE includes hooks to invoke your code under the right circumstances). For most programs it's not possible though -- they simply don't generate any "event" for you to hook and "destroy".
To make a long story short, to get anywhere with this, you'll almost certainly need to handle the situation on a case-by-base basis, writing code specific to each application you want to deal with -- and know that any other application and even newer versions of the applications you've dealt with will probably break what you're trying to do.
Not really. Consider how a browser typically downloads a file: it opens a TCP socket connection to a remote server, either on port 23 or 80, and using the FTP protocol or HTTP protocol on that connection. These things you can detect, intercept and modify with high reliability. But there are other programs that use other mthods. for instance, P2P filesharing programs such as BitTorrent do not use HTTP or FTP, nor do they download a file from a single server.
So, while you don't need to understand every program, you must be able to detect and understand every file download protocol instead.
you could hook the network stream and filter for http download requests.
you'll need some library to capture network traffic (e.g. http://en.wikipedia.org/wiki/Pcap).
Then you'll have to parse the network packets for the appropriate HTTP messages (sorry, I can't give them to you, I don't know them). I don't know if you can actually prevent packets from being sent though.
Another (easier) way would be to implement a proxy server (or modify an existing one) to do what you want. Then you just have to connect the IE to your proxy using the proxy server settings. Check for example Privoxy, which already does some kind of filtering.
I am writing an application, similar to Seti#Home, that allows users to run processing on their home machine, and then upload the result to the central server.
However, the final result is maybe a 10K binary file. (Processing to achieve this output is several hours.)
What is the simplest reliable automatic method to upload this file to the central server? What do I need to do server-side to prevent blocking? Perhaps having the client send mail is simple and reliable? NB the client program is currently written in Python, if that matters.
Email is not a good solution; you will run into potential ISP blocking and other anti-spam mechanisms.
The easiest way is over HTTP via a simple webservice. Have a listener at your server that accepts the uploaded files as part of a HTTP POST and then dump them wherever they need to be post-processed.
Ok so coming in from a completely different field of software development, I have a problem that's a little out of my experience. I'll state it as plainly as possible without giving out confidential details:
I want to make a server that "does stuff" when requested by a client on the same network. The client will most likely be a back-end to a content management system.
The request consists of some parameters, an input file and several output files.
The files are quite large, from 10MB - 100MB of data that must be processed (possibly more). The client can specify destination for output files.
The client needs to be able to find out the status of the request - eg position in queue, percent complete. And obviously when and where to pick up output.
So, my questions are - What is a good method for the client and server to communicate? Should the client poll the server, or provide a "callback" somehow for status updates?
At this point the implementation platform is completely open - anything from C to scripting languages like Ruby are available (at either end), my main issue is how the communication should occur.
First thought, set up some webservices between the machines. But webservices aren't going to be too friendly or efficient with the large files.
Simple appoach:
ServerA hits a web method on ServerB "BeginProcess". The response give you back a FTP location username/password, and ticket number.
ServerA delivers the files to FTP location.
ServerA regularly polls a webmethod "GetProcessStatus(ticketNumber)", possible return values: Awaiting files, Percent complete, Finished
Slightly more complicated approach, without the polling.
ServerA hits a web method on ServerB "BeginProcess(postUrl)", and you send along a URL you want status updates POSTed to. Response: FTP location username/password, and ticket number.
ServerA delivers the files to FTP location.
ServerB sends thru updates to the POST location on ServerA every XXX% completed.
For extra resilience you would keep the GetProcessStatus in case something gets lost in the ether...
Files that will be up to 100MB aren't a good choice for a webservice, since you run a risk of the HTTP session timing out before you have completed your processing.
Having a webservice for checking the status of these jobs would be more ideal. Handle the file transfers via FTP or whatever file transfer method you choose and poll a webservice for updates on status. When the process is completed, you might have an output file url returned that can be downloaded.