A library to expose the properties of any QObject derived C++ class via a REST API, a WebSocket JSONRPC API or both.

This example (obviously) depends on Qt and nothing else.

It has been tested with the following configurations:

• Apple LLVM verion 9.0.0 (clang-900.0.37)
• Qt 5.9.2

There is a minimal example project in the 'examples' folder which covers the following:

1. Add include (/path/to/qwebapi/src/qwebapi.pri) to your .pro file
2. Ensure the class you wish to expose extends Q_OBJECT and uses Q_PROPERTY to decorate the desired properties. For example:

testclass.h

#ifndef TESTCLASS_H #define TESTCLASS_H #include <QObject> class TestClass : public QObject { Q_OBJECT Q_CLASSINFO("Version", "0.1") Q_PROPERTY(int value READ value WRITE setValue NOTIFY valueChanged) public: explicit TestClass(QObject *parent = 0); int value(); signals: void valueChanged(int); public slots: void setValue(int value); void valueChangedSlot(int value); private: int _value; }; #endif // TESTCLASS_H

testclass.cpp

#include "testclass.h" #include <QDebug> TestClass::TestClass(QObject *parent) : QObject(parent), _value(42) { connect(this, SIGNAL(valueChanged(int)), SLOT(valueChangedSlot(int))); } int TestClass::value(){ return _value; } void TestClass::setValue(int value){ if(_value==value) return; _value=value; emit valueChanged(_value); } void TestClass::valueChangedSlot(int value){ qDebug() << "Value Changed:" << value; }

3. Create an instance of either RestApi() and/or WebSocketApi() and add the object you wish to expose as follows:

main.cpp

#include <QCoreApplication> #include "testclass.h" #include "restapi.h" #include "websocketapi.h" int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); TestClass *test=new TestClass; test->setObjectName("TestClass"); RestApi restApi; restApi.addObject<TestClass*>(test); WebSocketApi socketApi; socketApi.addObject<TestClass*>(test); return a.exec(); }

A URI is created for each property with the following format: /ClassName/PropertyName. So, for our example above the URI /TestClass/value would expose the value property. Because we specified both a setter (READ) and getter (WRITE) method, it ispossible to both get and set the property using this URI. If we wanted a read-only property then we could simply omit setter in the Q_PROPERTY specification.

Using the generated URI's is simple, for example using cURL from the command line:

$ curl http://localhost:<port>/TestClass/value # Get value $ curl -X PUT -d "new value" http://localhost:<port>/TestClass/value # Set value

The WebSocket API makes use of the JSON RPC standard message formats.

To get the value of a property:

{ "jsonrpc": "2.0", "method": "TestClass.value", "id": 1 }

The response will be in the following form:

{ "jsonrpc": "2.0", "id": 1, "result": 42 }

If a property defined a NOTIFY signal, then a message will be sent whenever this signal is emitted as follows:

{ "jsonrpc": "2.0", "method": "TestClass.valueChanged", "params": 1 }

A TypeScript RPC library is included in the 'clients/browser/typescript' folder along with an example HTML page.

Rudimentary documentation is provided via Doxygen. To generate the documentation, ensure Doxygen is installed then run the following:

$ cd /path/to/qwebapi/docs $ doxygen Doxyfile

This will create a folder of HTML documentation named 'html'. Browser into this folder and open 'index.html'.