I have a nodeJS server which receives user POST/Streaming requests from a web-UI.
I have a C++ back-end engine process which does some calculations and sends API calls to other 3rd party services. The API call requires certain info provided by the web users.
My question is what is the best solution to pass the request data received on NodeJS and send over to the C++ process?
WebUI -> NodeJS ->???->> C++ engine
Make your C++ application listen on a TCP or Unix socket.
Make your NodeJs application connect to that socket and exchange messages. For messages you can use Google Protocol Buffers, JSON, etc..
If the information what you have is still at JavaScript layer, then you have to implement C/C++ Addons implementation. If you already have some type of native module, then you may follow the same design based on that (very likely existing module could be based on NAN). If you are plan to introduce a brand new native module then it is a good time to consider N-API. You can get more information about it from.
https://nodejs.org/dist/latest-v11.x/docs/api/n-api.html
https://github.com/nodejs/node-addon-api
Related
I have a GUI (frontend, programmed in C++) and a kernel (backend, programmed in C++). Currently, the frontend is just linked to the backend library. However, due to performance reasons I want the functions from the library to be exceuted from another computer/server. The communication to the server shall be done via a TCP/IP connection.
The current idea to achieve this, is to set up a TCP/IP client/server connection. After the connection is set up the gui sends a header id and maybe additional data to the server, where the code is executed and the return is send back. However, to achieve this, I have to map every function to a header id and program the handling of the received data for every function in the backend. This is a tedious work, where I have to wrap each function manually.
The question is now: What is the common practice to connect the frontend to the backend via a server/client connection? And is there any generator (like SWIG for Python etc.) to generate a TCP/IP interface?
My application it's C++ service. And I need to add API for it. I consider that it will be XML/JSON RPC based API. How should I design a program for reusing existing code base and provide API.
I see following options:
My application will work via RPC layer. Seems that it's bad option due to low performance;
Before starting of service I will fork it and run my application in the first process and RPC server in the second; Seems ok, but how to restart RPC server in this case?
I guess there is a well known pattern for such issues.
Thanks.
If you can use a web server, then the FastCGI concept might be what you're looking for. One of the main duties of FastCGI is to allow you to put on a public API (from the web server) that internally calls the "real" application, in your case the resident C++ service. So all work is done at the web server to create the public API using any technology you wish, and little or no code changes done in your C++ service.
I'm looking for options that would allow a client to receive messages (push notifications) from a server. The client is an ARM/Linux embedded device similar in capabilities to a Raspberry Pi.
Because the client could be behind a firewall, I'd like to use message-oriented middleware (MOM) that can transport on top of HTTP. I think that rules out MOMs that are based on AMQP.
The MOM server should support the Linux platform. The MOM should also provide a C or C++ client library that can be compiled on an ARM/Linux platform.
I am aware of the HTTP long polling technique, as well as HTML 5 WebSockets and Server-Sent Events. But I'd prefer a higher-level (yet lightweight) solution that takes care of transporting messages between point A and point B over HTTP. It doesn't matter much if the messages have to be formatted as XML, JSON, plain text, or binary.
Two that I have used successfully are XML-RPC and gSOAP.
XML-RPC:
It's a spec and a set of implementations that allow software running on disparate operating systems, running in different environments to make procedure calls over the Internet.
It's remote procedure calling using HTTP as the transport and XML as the encoding. XML-RPC is designed to be as simple as possible, while allowing complex data structures to be transmitted, processed and returned.
gSOAP:
The gSOAP toolkit is a C and C++ software development toolkit for SOAP/XML Web services and generic (non-SOAP) C/C++ XML data bindings. The toolkit analyzes WSDLs and XML schemas (separately or as a combined set) and maps the XML schema types and the SOAP messaging protocols to easy-to-use and efficient C and C++ code. It also supports exposing (legacy) C and C++ applications as SOAP/XML Web services by auto-generating XML serialization code and WSDL specifications. Or you can simply use it to automatically convert XML to/from C and C++ data. The toolkit supports options to generate pure ANSI C or C++ with or without STL.
According to my research, these are the available MOM technologies that use HTTP as a transport, and which feature a C/C++ client library:
XMPP
Extensible Messaging and Presence Protocol (XMPP) is a communications
protocol for message-oriented middleware based on XML (Extensible
Markup Language).The protocol was originally named Jabber, and
was developed by the Jabber open-source community in 1999 for near
real-time, instant messaging (IM), presence information, and contact
list maintenance. Designed to be extensible, the protocol has also
been used for publish-subscribe systems, signalling for VoIP, video,
file transfer, gaming, Internet of Things applications such as the
smart grid, and social networking services. (from Wikipedia)
ActiveMQ
Apache ActiveMQ is an open source message broker written in Java
together with a full Java Message Service (JMS) client. It provides
"Enterprise Features" which in this case means fostering the
communication from more than one client or server. Supported clients
include the obvious Java via JMS 1.1 as well as several other "cross
language" clients. The communication is managed with features such as
computer clustering and ability to use any database as a JMS
persistence provider besides virtual memory, cache, and journal
persistency. (from Wikipedia)
Zerogw
Zerogw is a http to zeromq gateway. Which means it listens HTTP,
parses request and sends it using zeromq socket (ZMQ_REQ). Then waits
for the reply and responds with data received from zeromq socket.
Starting with v0.3 zerogw also supports WebSockets. Websockets are
implemented by forwarding incoming messages using ZMQ_PUB socket, and
listening clommands from ZMQ_SUB socket. Each WebSocket client can be
subscribed to unlimited number of topics. Each zeromq message it
either control message (e.g. subscription) or message to a specified
topic which will be efficiently sent to every WebSocket subscribed to
that particular topic. (from the GitHub zerogw page)
There's also the HyperText InterORB Protocol (HTIOP), but TAO seems to be the only CORBA ORB that supports it. There doesn't seem to be anyone using it (please correct me if I'm wrong).
There is work in progress to make OMG's Data Distribution Service (DDS) web-enabled.
I'm also warming up to the idea of using WebSockets for bidirectional communications, despite their "low level" nature. For those interested, available C/C++ libraries include:
libwebsockets
websocket++
QWebSockets
Wt (C++ web development toolkit which includes support for WebSockets)
There is an open Websocket Application Messaging Protocol (WAMP) that provides asynchronous messaging patterns for remote procedure calls and the publish-subscribe pattern. There are a number of implementations for WAMP, but none of them are written in C/C++.
i am writing an program in c++ and i need an web interface to control the program and which will be efficient and best programming language ...
Your application will just have to listen to messages from the network that your web application would send to it.
Any web application (whatever the language) implementation could use sockets so don't worry about the details, just make sure your application manage messages that you made a protocol for.
Now, if you want to keep it all C++, you could use CPPCMS for your web application.
If it were Windows, I could advice you to register some COM component for your program. At least from ASP.NET it is easily accessible.
You could try some in-memory exchange techniques like reading/writing over a localhost socket connection. It however requires you to design some exchange protocol first.
Or data exchange via a database. You program writes/reads data from the database, the web front-end reads/writes data to the database.
You could use a framework like Thrift to communicate between a PHP/Python/Ruby/whatever webapp and a C++ daemon, or you could even go the extra mile (probably harder than just using something like Thrift) and write language bindings for the scripting language of your choice.
Either of the two options gives you the ability to write web-facing code in a language more suitable for the task while keeping the "heavy lifting" in C++.
Did you take a look at Wt? It's a widget-centric C++ framework for web applications, has a solid MVC system, an ORM, ...
The Win32 API method.
MSDN - Getting Started with Winsock:
http://msdn.microsoft.com/en-us/library/ms738545%28v=VS.85%29.aspx
(Since you didn't specify an OS, we're assuming Windows)
This is not as simple as it seems!
There is a mis-match between your C++ program (which presumibly is long running otherwise why would it need controlling) and a typical web program which starts up when it receives the http request and dies once the reply is sent.
You could possibly use one of the Java based web servers where it is possible to have a long running task.
Alternatively you could use a database or other storage as the communication medium:-
You program periodically writes it current status to a well know table, when a user invokes the control application it reads the current status and gives an appropriate set of options to the user which can then be stored in the DB, and actioned by your program the next time it polls for a request.
This works better if you have a queuing mechanism avaiable, as it can then be event driven rather than polled.
Go PHP :) Look at this Program execution Functions
In a normal client/server design, the client can execute functions implemented on the server-side. Is it possible to test a gSOAP server by connecting an extra client to it?
I have not used gSOAP, but from reading the documentation it allows you to write both clients and servers so you can write an test client to test the service.
However if you are planning to offer the service to clients written in .net or java I would recommend that you write the test client in one of these. This way you will know for certain that it is possible to use the service from one of these clients. You might also find that .net or java clients are easier to write if you server is designed in a specific way, your test client will help you find this out.
Sure it is, use SoapUI to generate client connections and data. Its free.
To add to the other comments: testing a gSOAP server can be easily done offline using IO redirect. When you invoke soap_serve() without any sockets set up prior to this call, the server engine will simply accept data from standard input and write data to standard output. This is a great way to hit an offline server implementation hard with XML data patterns for testing before deploying the server online. The gSOAP tool even generates example XML messages that you can use for this purpose.