I am using Cgicc , which has some methods to extract specific request headers, e.g. getUserAgent would return "User-Agent" header.
Is there a generic method that can return an arbitrary header value, e.g. something like
getHeaderValue("x-my-header");
Is there a way to do this using cgicc? and if cannot be done with cgicc, how else can I extract a custom header from the request in c++?
No, cgicc does not support this direcly. However, it is just a wrapper around CGI. http://en.wikipedia.org/wiki/Common_Gateway_Interface and it uses "getenv" in CgiInput
class to extract all information provided by the web server.
So if the client send some header that is not supported directly by CgiCC but does supported by the web server (lets say Accept-Encoding:) that you just need to read apropriate
environment variable getenv("HTTP_ACCEPT_ENCODING")
But it should be supported by web server you are working with
EDIT: actually according CGI RFC http://www.ietf.org/rfc/rfc3875.txt web server should provide enviroment variable for your example: HTTP_X_MY_HEADER
Related
How can I use dynamic WSDL, it's operations and parameters, which is given in program config file?
For example, we have a config file:
[Section]
WSDL=http://example.com/SomePub/ws/SomeService?wsdl
Username=myuser
Password=mypass
OperationName=MyOperation
ParameterName=MyParameter
I.e. we have to use web-service, which is unknown, but given (by ini-file) only in run-time. So, we cannot use WSDL Import wizard in Delphi.
Can we write in Delphi such a program, which would load these settings from configuration, and then pass data to specified operation in specified parameter on web-service, which specified by given WSDL?
Using SOAPUI, import the service and perform a sample call. Copy the raw request and the raw response into notepad. Modify the real data with 'tags' and include each raw template as a value in your INI. When you need to make the call, open your INI, grab the raw response template and replace tags with real values. Manually send the SOAP request and parse the response in the same way using the raw template.
The Delphi WSDL importer and the Free Pascal Web Service Toolkit do not provide a way to build a SOAP request dynamically based on a WSDL.
The Web Service Toolkit (and the WSDL importer) are only source code generators, so the code first needs to be compiled - this requires to include a compiler with your application.
In my C++ app I'm embedding (via COM) a web browser (Internet Explorer) control (CLSID_WebBrowser).
I can display my own html in that control by using IHTMLDocument2::write() method but if the html has <img src="foo.png"> element, it's not displayed.
I assume there is a way for me to provide the data for foo.png somehow to the web control, but I can't find the right place to hook this functionality?
I need to be in full control of providing the content of foo.png, so work-arounds like using res:// protocol or saving to disk and using file:// protocol are not good enough. I just want to plug my code somehow so that when embedded CLSID_WebBrowser control sees <img src="foo.png"> in html data given with IHTMLDocument2::write() it will ask me to provide this data.
To answer my own question, the solution that finally worked for me is:
register custom IInternetProtocol/IInternetProtocolInfo/ via custom IClassFactory given to IInternetSession::RegisterNameSpace(). For reasons that seem like a bug to me, it has to be a protocol already known to IE (I've chosen "its") even though it would be much better if it was my own, unique namespace.
feed html data via custom IMoniker through IPersistentMoniker::Load() and make sure that IMoniker::GetDisplayName() (which is a base url according to which relative links in provided html will be resolved) starts with that protocol scheme (in my case "its://"). That way relative link "foo.png" in the html data will be its://foo.png to IE which will make urlmon call IInternetProtocol::Start() and IInternetProtocol::Read() to ask for the data for that url.
This is all rather complicated, you can look at the actual (BSD-licensed) code here:
http://code.google.com/p/sumatrapdf/source/browse/trunk/src/utils/HtmlWindow.cpp
You can embed a small webserver such as mongoose and reference those impage from there.
In mongoose, you can attach callback to specific path, thus returning images from C++ code.
We use this for our debugging tools, where each images is accessible from a web interface
The easiest solution would be a Data URI. You'd inline out the image directly with IHTMLDocument2::write().
I'm using lib-cURL as a HTTP client to retrieve various pages (can be any URL for that matter).
Usually the data comes as a UTF-8 string and then I just call "MultiByteToWideChar" and it works well.
However, some web-pages still use code-page encoding and I see gibberish if i try to convert those pages to UTF-8.
Is there an easy way to retrieve the code page from the data? or I'll have to scan it manually (for "encoding=") and then translate it accordingly.
If so, how do i get the code-page id from name (Code Page Identifiers)?
Thanks,
Omer
There are several location where a document can state its encoding:
the Content-Type HTTP header
the (optional) XML declaration
the Content-Type meta tag inside the document header
for HTML5 documents the charset meta tag.
There are probably even more I've forgotten.
In the end, detecting the actual encoding is rather hard. You really shouldn't do this yourself but use high-level libraries for retrieving and parsing HTML content. I'm sure they are available even for C++, even if they have to be thiefed from the a browser environment. :)
I used DetectInputCodepage in IMultiLanguage2 interface and it worked great !
i am trying to find out, how to get input from html inputs using c++. In windows you can send WM_GETTEXT to the window and it returns text, that you wanted. But is there any way to do the same thing in web interface?.
I am not interesting in sniffing packets now.
For example. Some site has html intput which expects name. I write name to the input. And then i want to catch it with my program
If I understood correctly what you want to do, you have to set up a web server that calls your C++ application via CGI. So, you'll have an HTML page (static or generated by your program) that will contain a form, that refers to the URL of your application. So, when the user will click Submit, the browser will issue a request to the webserver, which in turn will call your application, passing to it the various POST/GET parameters related to the form.
Your application then can process the data, extracting such parameters from the environment variables (if the data is passed using the GET method) or from the standard input (if the POST method is used). To generate the output page (along with the output HTTP header) you'll simply have to write it to the standard output.
One thing I can think of (if you're using Linux) is using wget via system() from within your C++ app.
Wget to fetch the html page and output it to a file, parse the file for the URL of the form and data that it needs, pass the response as POST / GET via wget and so on.
That is, if I understood what you meant by "do it from existing page" correctly.
I am trying to find the best way (most efficient way) to return large files from Django back to an http client.
receive http get request
read large file from disk
return the content of that file
I don't want to read the file then post the response using HttpResponse as the file content is first stored in RAM if I am correct. How can I do that efficiently ?
Laurent
Look into mod_xsendfile on Apache (or equivalents for nginx, etc) if you like to use Django for authentication. Otherwise, there's no need to hit django, and just server straight from Apache.
There is a ticket that aims to deal with this problem here: http://code.djangoproject.com/ticket/2131
It adds an HttpResponseSendFile class that uses sendfile() to send the file, which transparently sends the file as it's read.
However, the standard HttpResponse is implemented as an iterator, so if you pass it a file-like object, it will follow its iteration semantics, so presumably you could create a file-like object wrapper that chunks the file in small enough pieces before sending them out.
I believe the semantics of iterating over a standard file object in python is that it reads line-by-line, which most likely won't solve your problem if you're dealing with binary files.
Of course, you could always put the static files in another location and serve that with a normal web server, unless you require intricate control (like access control requiring knowledge of the Django database)
My preference for all of this is to synthesize django with your http server so that when you want to serve static files, you simply refer them to a path that will never reach django. The strategy will look something like this:
Configure http server so that some requests go to django and some go to a static document root
link to static documents from any web pages that obviously need the static documents (e.g. css, javascript, etc.)
for any non-obvious return of a static document, use an HttpRedirect("/web-path/to/doc").
If you need to include the static document inside a dynamic document (maybe a page-viewer wrapping a large text or binary file), then return a wrapper page that populates a div with an ajax call to your static document.