kandi X-RAY | cpprestsdk Summary
kandi X-RAY | cpprestsdk Summary
The C++ REST SDK is a Microsoft project for cloud-based client-server communication in native code using a modern asynchronous C++ API design. This project aims to help C++ developers connect to and interact with services.
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cpprestsdk Key Features
cpprestsdk Examples and Code Snippets
Trending Discussions on cpprestsdk
I created a simple client and server using
CPPRESTSDK. The client sends an image and on the server, I save the incoming file and then start doing the processing phase afterwards.
Now I want to check if the sent file is actually an image file and not some other random file. For that, I check the first few bytes of the file and this allows me to know what I'm dealing with.
This is the snippet responsible for saving the file:
ANSWERAnswered 2021-Mar-07 at 02:45
You need to open the file stream for both reading and writing, by explicitly passing the
mode parameter to the
open_ostream function. If you don't specify this parameter, it defaults to
I am trying to make a server by looking at the sample code of cpprestSDK. But I don't know why I bind in the sample code.
Below is the sample code.
ANSWERAnswered 2020-Sep-01 at 13:56
The member function
I have been looking at the memory usage of some C++ REST API frameworks in Windows and Linux (Debian). In particular, I have looked at these two frameworks: cpprestsdk and cpp-httplib. In both, a thread pool is created and used to service requests.
I took the thread pool implementation from cpp-httplib and put it in a minimal working example below, to show the memory usage that I am observing on Windows and Linux....
ANSWERAnswered 2020-Aug-22 at 03:10
Many modern allocators, including the one in glibc 2.17 that you are using, use multiple arenas (a structure which tracks free memory regions) in order to avoid contention between threads which want to allocate at the same time.
Memory freed back to one arena isn't available to be allocated by another arena (unless some type of cross-arena transfer is triggered).
By default, glibc will allocate new arenas every time a new thread makes an allocation, until a predefined limit is hit (which defaults to 8 * number of CPUs) as you can see by examining the code.
One consequence of this is that memory allocated then freed on a thread may not be available to other threads since they are using separate areas, even if that thread isn't doing any useful work.
You can try setting the glibc malloc tunable
1 in order to force all threads to the same arena and see if it changes the behavior you were observing.
Note that this has everything to do with the userspace allocator (in libc) and nothing to do with the OS allocation of memory: the OS is never informed that the memory has been freed. Even if you force a single arena, it doesn't mean that the userspace allocator will decide to inform the OS: it may simply keep the memory around to satisfy a future request (there are tunables to adjust this behavior also).
However, in your test using a single arena should be enough to prevent the constantly increasing memory footprint since the memory is freed before the next thread starts, and so we expect it to be reused by the next task, which starts on a different thread.
Finally, it is worth pointing out that what happens is highly dependent on exactly how threads are notified by the condition variable: presumably Linux uses a FIFO behavior, where the most recently queued (waiting) thread will be the last to be notified. This causes you to cycle through all the threads as you add tasks, causing many arenas to be created. A more efficient pattern (for a variety of reasons) is a LIFO policy: use the most recently enqueued thread for the next job. This would cause the same thread to be repeatedly reused in your test and "solve" the problem.
Final note: many allocators, but not the on in the older version of glibc that you are using, also implement a per-thread cache which allows the allocation fast path to proceed without any atomic operations. This can produce a similar effect to the use of multiple arenas, and which keeps scaling with the number of threads.
I am using cpprestsdk (casabalanca) to POST a request to a server and I have a list of parameters...
ANSWERAnswered 2020-Jul-10 at 10:24
Found the solution...
looking at how high level languages, like Java, C# and Python handle http requests as a client, I'm wondering what the default approach is in c++ today.
My requirements are:
- HTTP Client for a REST Interface
- HTTP over SSL
- Support of OAuth2 Client credentials
The OAuth2 support I scratched very fast and accepted, that this needs to implemented.
I found a number of libraries, but most of them appear to be rather outdated and a bit "unprofessional".
So here is a list of what I could find and what my thoughts are about these:
While this appears to be the most professional choice. The C API is a bummer and of course the OAuth support does not exist. But this seems to be the optimal choice for me right now.
A c++ wrapper for libcurl and it appears to be a rather badly maintained library, which is a nono. It appears to have https support, but in the github md it says it hasnt.
This project appears to be not maintained anymore.
If I am not mistaken, I have to do everythings myself here. I am trying to get sth. done and don't want to reinvent the wheel.
While it doesn't look bad, I'm kind of reluctant towards using a UI framework for communication. But maybe I'm mistaken.
While looking good for my purpose at first, OAuth2 client credentials are not supported. The whole OAuth2 part is flagged as experimental. And thats the case for a few years now. Seems to be unfinished and badly maintained.
So probably c++ isn't the usual language you do http client stuff in, but this is such a basic thing, that I'm suprised about the libraries that are out there.
Did I miss anything big?
What is the default approach at this? Is there a better "high level" choice. Or is the default approach doing it low level boost::asio style for optimal performance?...
ANSWERAnswered 2020-Jan-12 at 20:38
No vulnerabilities reported
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