skycoder42 / qtjsonserializer Goto Github PK

How can QObject derived object with child objects be used with QtJsonSerializer? I mean that QObject already has children() getter. Is it possible to reuse embedded child-parent methods in collaboration with Q_PROPERTY instead of explicit adding m_children field?

If the struct (Q_GADGETed) contains QVector, what can be done in order to make your library work? I've read about registering QList's, but QVector is also very popular data structure. It is considered as a default choice in Qt5 docs (older Qt4 docs advertized QList).

Hello! I have to use 3.x and 4.x versions of QtJsonSerializer in different projects.
The problem is that Qt subdir gcc_64/include/QtJsonSerializer/ contains headers which are different for 3.x and 4.x. Why don't these specific headers stay in 4.x and 3.x subdirs? For example, jsonserializer.h.

When I call make on 4.0.3 I'm getting this. I've built the last several versions and have never had this problem.

/Qt_Commercial/5.14.1/QtJsonSerializer-4.0.3/src/jsonserializer/qjsonreggen.py /Qt_Commercial/5.14.1/QtJsonSerializer-4.0.3/src/jsonserializer/.reggen/qjsonconverterreg_bool.cpp bool
env: python3: No such file or directory
make[2]: *** [/Qt_Commercial/5.14.1/QtJsonSerializer-4.0.3/src/jsonserializer/.reggen/qjsonconverterreg_bool.cpp] Error 127
make[1]: *** [sub-jsonserializer-make_first] Error 2
make: *** [sub-src-make_first] Error 2

Hello! I'd like my Q_GADGETS to convert to JSON and vice versa without external calls to QtJsonSerializer.
So, I mean QtJsonSerializer encapsulation. I've got a base class

class JsonSerializable 
{
Q_GADGET

public:
  JsonSerializable(const QByteArray& json)
{
//TODO
}

operator QString() const
{
	return toJson();
}

QByteArray toJson() const 
{
	//return result from QtJsonSerializer
}
 

};

But what about creation of this object from QByteArray (JSON) in ctor? I'd like to minimize redundant copies.

Hi I'm using Qt version 5.10.0.
I get this error when serializing this class :
`class Spectra : public QObject
{
Q_OBJECT
Q_ENUM(SpectrumType)
Q_ENUM(SpectrumPolarization)
Q_PROPERTY(double incidenceAngle MEMBER incidenceAngle)
Q_PROPERTY(SpectrumType type MEMBER type)
Q_PROPERTY(SpectrumPolarization polarization MEMBER polarization)

public:
Q_INVOKABLE Spectra(QObject *parent = nullptr) : QObject(parent)
{
type = ST_Reflectance;
incidenceAngle = 0.0;
polarization = SP_Unpolarized;
}

~Spectra(){}

double incidenceAngle;
SpectrumType type;
SpectrumPolarization polarization;

};

Q_DECLARE_METATYPE(Spectra *) `

At runtime it says ;
QMetaProperty::read: Unable to handle unregistered datatype 'SpectrumType' for property 'Spectra::type'
QMetaProperty::read: Unable to handle unregistered datatype 'SpectrumPolarization' for property 'Spectra::polarization'

Then serializes the object as depicted below
{ "spectraList": [ { "incidenceAngle": 0, "polarization": null, "type": null } ] }
To register datatypes I added required meta type declarations;

Q_DECLARE_METATYPE(SpectrumType) Q_DECLARE_METATYPE(SpectrumPolarization)
This time QtJsonserializer throws exeption and crashes;
terminate called after throwing an instance of 'QJsonSerializationException' what(): what: Failed to serialize with error: Failed to convert type SpectrumType to a JSON representation Property Trace: spectraList (Type: QList<Spectra*>) [0] (Type: Spectra*) type (Type: SpectrumType)

Hello!
I am trying to serialize Q_GADGET struct (My_gadget). It contains QVariantList children.
These children are QVariant values which encapsulate My_gadget. The corresponding property is not serialized (it's a pity). If i change to QVariant child, then it fails too. What is the workaround?
In real project QVariantList will contain other Q_GADGETs too.

P.S. AFAIK, CBOR is used internally in this serializer even if I need JSON. Q_GADGET struct fails to convert to QCBorValue via QVariant wrapper, because QVariant::toString() returns empty string.

I have a class definition as followed (In shortly):

class Model : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QList<std::complex<double>> Chi MEMBER Chi)

protected:

    QList <std::complex<double>> Chi;
}

And I declared the metatype as you stated:
Q_DECLARE_METATYPE(std::complex<double>)
In usage, I register the list as you suggested;
QJsonSerializer::registerListConverters<std::complex<double>>();

And when It comes to serilaze it throws exception and terminates:

terminate called after throwing an instance of 'QJsonSerializationException'
  what():  what: Failed to serialize with error: Failed to convert type std::complex<double> to a JSON representation
Property Trace:
        Chi (Type: QList<std::complex<double> >)
        [0] (Type: std::complex<double>)

This application has requested the Runtime to terminate it in an unusual way.

I know it is a matter of conversion thing and It would be lifesaver resolving this.

Regards

I have a library that used CMake, and I want to link my library with QtJsonSerializer, but QtJsonSerializer used qmake, therefore it's hard linking between two libraries.

Hello! I think that sometimes it's helpful to have an ability to serialize properties even with STORED=false.
For example, we save all properties for output in debug log and subset of properties with STORED=true for REST service response.

Greetings,

first off, thank you very much for this wonderful library, it makes JSON serialization much easier to deal with. Thanks a lot!

However, how do you declare a class that inherit a container with the type already given? I have the current code, which works but this produce an ugly QJsonObject rather than a nice and simple QJsonArray like I would want it to be or is this simply not possible? Thank you very much!

foo.hpp

class Foobar
{
    Q_GADGET

    Q_PROPERTY(QString name MEMBER m_name)

public:
    QString m_name;
};
Q_DECLARE_METATYPE(Foobar)

class FoobarList : public QList<Foobar>
{
    Q_GADGET

    Q_PROPERTY(QJsonArray a READ getFoobarList WRITE setFoobarList)

public:
    static void registerMetaType()
    {
        qRegisterMetaType<FoobarList>();
        QtJsonSerializer::JsonSerializer::registerListConverters<FoobarList>();
    }

    FoobarList(const QList<Foobar> &a = QList<Foobar>())
        : QList(a)
    {}
    QJsonArray getFoobarList() const
    {
        /** do something **/
        
        return QJsonArray();
    }
    void setFoobarList(const QJsonArray &a)
    {
        /** do something **/
    }
};
Q_DECLARE_METATYPE(FoobarList)
Q_DECLARE_TYPEINFO(FoobarList, Q_MOVABLE_TYPE);

foo.cpp

namespace
{
    void registerMetaType()
    {
        FoobarList::registerMetaType();
    }
} // namespace
Q_COREAPP_STARTUP_FUNCTION(registerMetaType)

Expected output:

[
    "Foo0000",
    "Foo0001",
    "Foo0002"
]

Current output:

[
    {
        "name": "Foo0000"
    },
    {
        "name": "Foo0001"
    },
    {
          "name": "Foo0002"
    }
]

Hello! I have 10000 PODs. Each POD contains primitive properties, so CBOR<->QVariant conversion can be done without iterating converter "store" (more than 20 checks a-la canConvert are done before switching to default conversion). So, using helper()->serializeSubtype is expensive for primitive types. Is it possible to improve performance if we deal with simple types? I don't want to subclass converter in order to speed up conversion.

Hello! I'd like to serialize Q_GADGET member QSet<MyEnum> enumSet as a set of int's. But serialization converts it to string, though I didn't called setEnumAsString(true).

I would like to update all or selected properties of an existing object. Is it possible to do it with QtJsonSerializer?

Right now I am writing such de-serialization functions myself, but it is a bit tedious.

registerSetConverters results in build time error no matching function to call qHash(...
my class

class simpleGadget
{
    Q_GADGET
    Q_PROPERTY(int id MEMBER id)
    Q_PROPERTY(bool flag MEMBER flag);
    Q_PROPERTY(float fValue MEMBER fValue);
    Q_PROPERTY(double dValue MEMBER dValue);
    Q_PROPERTY(long lValue MEMBER lValue);
    Q_PROPERTY(QString sValue MEMBER sValue);
    Q_PROPERTY(QList<int> iValues MEMBER iValues);
    Q_PROPERTY(QByteArray byteValue MEMBER byteValue);
public:
    simpleGadget(){}
    ~simpleGadget(){}
    int id = -1;
    bool flag = true;
    float fValue = 3.14;
    double dValue = 33.5555555;
    long lValue = 100000;
    QByteArray byteValue = "1234567A";
    QString sValue = "Hello World";
    QList<int> iValues = {1,2,3};
    QByteArray expectedJson = "{\"byteValue\":\"MTIzNDU2N0E=\",\"dValue\":33.5555555,\"fValue\":3.140000104904175,\"flag\":true,\"iValues\":[1,2,3],\"id\":-1,\"lValue\":\"100000\",\"sValue\":\"Hello World\"}";
    bool operator==(const simpleGadget& newValue) const
    {
        return (id == newValue.id &&
                flag == newValue.flag &&
                fValue == newValue.fValue &&
                dValue == newValue.dValue &&
                lValue == newValue.lValue &&
                sValue == newValue.sValue &&
                iValues == newValue.iValues &&
                byteValue == newValue.byteValue);
    }

    bool operator!=(const simpleGadget& newValue) const
    {
        return !(*this == newValue);
    }
};
Q_DECLARE_METATYPE(simpleGadget)

Hello! I have to switch to bare metal ARM (Xilinx Zynq-7000).
I have plenty of PODs (Q_GADGET's) for JSON serialization.
I cannot use Qt for MCUs. Is it technically possible to adapt QtJsonSerializer for CopperSpice support? I mean using reduced version of CsCore and QtJsonSerializer for bare metal. Surely, I don't ask you to do this task, just want to know whether it requires a lot of work or is totally impossible.
P.S. Bare metal doesn't imply a memory size, it only means that there's no full-blown operating system.

Hi,
I compiled the QtJsonSerializer, and installed.
Then try to run sample, the only change was to Sample.pro where I added CONFIG += c++1z
If I run the Sample application from the command line I get the following output:

Serializing SampleGadget:
{
    "base": [
        42,
        13
    ],
    "rawData": {
        "someData": false
    }
}


And deserializing data back:
base: QPoint(42,13)
rawData: {
    "someData": false
}


Now the test object, with the previous gadget as child:
terminate called after throwing an instance of 'QtJsonSerializer::SerializationException'
  what():  what: Failed to serialize with error: Unable to determine typeid of meta enum SampleObject::SuperFlags
Property Trace:
	flags (Type: SuperFlags)
Annullato (core dump creato)

System is Ubuntu 16.04 with:
Qt v5.14.2
g++ v7.5.0

HI @Skycoder42
I got the error with build example
I follow the command

qmake && make && make install

Hey Felix, I'm trying to build the module as a static lib on Windows to link with my executable so I don't have to deploy the .dll. I've used the Qt MaintenanceTool as per your instructions to add the module to my Qt source tree as user defined repo. I rebuilt Qt (5.11.2) statically from source using configure and jom. It looks the QtJsonSerializer has not been built along with Qt base and the other default Qt modules, I don't see the QtJsonSerializer lib.

Do you know the configure switch or procedure to build your module as part of a QT from source build under Windows?

Alternatively, how would I just add the module sources to my Qt App project and have it built along with the app and linked in statically?

A third way I can think of would be to separately build just QtSerializer statically in one step and add the .lib to my App .pro file. Attempting this using qmake and jom yield path issues for files not being compiled/generated (LINK : fatal error LNK1181: Input ".obj\release\qjsonconverterreg_0.obj" could not be opened).

I understand you have pre-built binaries for various platforms on your release page - these are dynamic libs however and need the runtime Dll.

Any help or hint is appreciated. Thanks!

• Ben

Hi all
I build this source code on windows and macos with Qt5.10.1.but I got some errors

/Qt5.10.1/5.10.1/clang_64/lib/QtCore.framework/Headers/qhashfunctions.h:112:35: error: no matching function for call to 'qHash'
    Q_DECL_NOEXCEPT_EXPR(noexcept(qHash(t)))

 FullValidation = (NoExtraProperties | AllProperties)
//        FullValidation Q_DECL_ENUMERATOR_DEPRECATED_X("Use QJsonSerializer::FullValidation2 or QJsonSerializer::FullPropertyValidation instead") = (NoExtraProperties | AllProperties)

and source code

#if !defined(QT_NO_EXCEPTIONS) //&& QT_CONFIG(future)
#include <QtCore/qexception.h>
#define QT_JSONSERIALIZER_EXCEPTION_BASE QException
#define QT_JSONSERIALIZER_EXCEPTION_OR override
#else
#include <exception>
#define QT_JSONSERIALIZER_EXCEPTION_BASE std::exception
#define QT_JSONSERIALIZER_EXCEPTION_OR
#endif

what's wrong with my platform or build tools?

Hello! What should I do if I have multiple custom embedded types?
For example, matryoshka;

Gadget_A {
    QList<B> b_list;
};
//...
Gadget_B {
    QList<C> c_list;
};
//...
Gadget_C: {
    QString name;
};

What are the tricks for tracking such types? I mean QJsonSerializer::registerListConverters() usage. For example, if we use Q_DECLARE_METATYPE, then we put it after class declaration,
Placing QJsonSerializer::registerListConverters() in main.cpp is more error-prone.

I get this error
"too many arguments provided to function-like macro invocation"

using QMap as Property:
Q_PROPERTY( QMap<QString, myClass*> mylist MEMBER mylist )

I did a lot of investigating in the net and the result is, that Q_PROPERTY is a macro of Q_OBJECT, which doesn't support variadic templates, so the comma necessary to define the QMap within Q_PROPERTY macro is not supported.

The only way to remove the error is to bundle the QMap definition in a Typedef, but seems to be not supported in QJsonSerializer library.

In the examples there is no example for using QMap; maybe I used it wrong.

Could you add a example how to use QMap with custom class to serialize and deserialize?

Just as the title says how to do it?

Hello! Do you have any hints concerning (de-)serialization of polymorphic Q_GADGETs? They can also have Q_CLASSINFO. I suppose that I have to create a "switch" for property getter/setter which checks some flag in JSON. It will choose, in fact, among variant.value<Class1>(), variant.value<Class2>() and so on for deserialization.

Please, add support for Visual Studio 2013 (at least, just in source, no binary releases required). It is not so old to be neglected. I've met error C3646: 'noexcept'. This keyword is absent in VS 2013.
Here are workarounds for inspiration:
https://stackoverflow.com/questions/18387640/how-to-deal-with-noexcept-in-visual-studio

QT version: 5.14.1
QtJsonSerializer install way: Download the compiled modules from the release page.
System: windows 10
Build setting: Qt_5_14_1_MSVC2017_64bit-Debug

No changes have been made to the sample code except to add 'CONFIG += c++17 ' to 'Sample.pro'.

Exceptions are shown in the figure below:

Hello! I've got the following error for generated qjsonconverterreg_*.cpp files: warning C4335: Mac file format detected: please convert the source file to either DOS or UNIX format.
I suppose that wrong line endings prevent me from debugging within Visual Studio 2017.

Assuming I have some code like this
QList<QSharedPointer> aList;
QSharedPointer tmp(new SampleObject());
aList.append(tmp);
aList.append(tmp);
auto jsonarray = serializer.serialize(aList);
qDebug() << "\nSerialize a QList now:";
qDebug() << JSON_PRINT(jsonarray);

Then the generated JSON has duplicates of the object. Clearly this will not restored as intended.
The application code could use "names" or some other "ids" to prevent duplication as a workaround.
Just wondering if this has been thought of/dealt with by others.

Any Example to Serialize QSqlQuery Or QSqlQueryModel

Hello! I can't build your library using Qt 5.11.2 in Windows (MS VS 2017). But Qt 5.12.1 works fine. At least, please, add minimal supported Qt version.

Creating library ....\lib\Qt5JsonSerializerd.lib and object ....\lib\Qt5JsonSerializerd.exp
qjsonconverterreg_22.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) unsigned int __cdecl qHash(class QJsonValue const &,unsigned int)" (_imp?qHash@@YAIAEBVQJsonValue@@i@Z) referenced in function "private: struct QHashNode<class QJsonValue,struct QHashDummyValue> * * __cdecl QHash<class QJsonValue,struct QHashDummyValue>::findNode(class QJsonValue const &,unsigned int *)const " (?findNode@?$QHash@VQJsonValue@@UQHashDummyValue@@@@AEBAPEAPEAU?$QHashNode@VQJsonValue@@UQHashDummyValue@@@@AEBVQJsonValue@@peai@Z)
qjsonconverterreg_23.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) unsigned int __cdecl qHash(class QJsonObject const &,unsigned int)" (_imp?qHash@@YAIAEBVQJsonObject@@i@Z) referenced in function "private: struct QHashNode<class QJsonObject,struct QHashDummyValue> * * __cdecl QHash<class QJsonObject,struct QHashDummyValue>::findNode(class QJsonObject const &,unsigned int *)const " (?findNode@?$QHash@VQJsonObject@@UQHashDummyValue@@@@AEBAPEAPEAU?$QHashNode@VQJsonObject@@UQHashDummyValue@@@@AEBVQJsonObject@@peai@Z)
qjsonconverterreg_24.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) unsigned int __cdecl qHash(class QJsonArray const &,unsigned int)" (_imp?qHash@@YAIAEBVQJsonArray@@i@Z) referenced in function "private: struct QHashNode<class QJsonArray,struct QHashDummyValue> * * __cdecl QHash<class QJsonArray,struct QHashDummyValue>::findNode(class QJsonArray const &,unsigned int *)const " (?findNode@?$QHash@VQJsonArray@@UQHashDummyValue@@@@AEBAPEAPEAU?$QHashNode@VQJsonArray@@UQHashDummyValue@@@@AEBVQJsonArray@@peai@Z)
....\lib\Qt5JsonSerializerd.dll : fatal error LNK1120: 3 unresolved externals
NMAKE : fatal error U1077: '"D:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.16.27023\bin\HostX64\x64\link.EXE"' : return code '0x460'
Stop.

Hello! I have a static version of Qt 5.12 (Windows). QtJsonSerializer was installed as a static lib. But the problem is linked with Q_JSONSERIALIZER_EXPORT define. It is redundant for static version. How this can be fixed? I prefer CMake (Qt developers even dropped qbs, qmake will be obsolete too in the far future, the will concentrate on CMake). BTW, I use QtJsonSerializer CMake module.

MaintenanceTool: Qt5.14.1/MaintenanceTool.exe

Hello!
I have QVariant field1 within Q_GADGET (JSON serialization). This field contain QPair<int,int> (for example). field1 can contain some gadgets, each one is linked with Gadget_type enum. Gadget contains Gadget_type field2 (enum which depicts actual data type).
I've added all typical metatype registration stuff, including QMetaType::registerConverter. The result field value is in quotes: "field1":"[1,2]". The problem is linked with deserialization exception:

Failed to deserialize with error: Failed to convert deserialized variant of type QString to property type QVariant. Make shure to register converters with the QJsonSerializer::register* methods.

Hello,
Is it technically possible to have Q_INVOKABLE constructor that takes some parameters when deserializing a QObject ??

Please as the latest version available through the repository is 5.14.1.

Let's assume that we have an old C enum wrapped inside of the Q_GADGET struct:

struct MyEnumWrapper
{
 Q_GADGET
 //re-open public visibility after Q_GADGET
 public:
 enum Enum
 {
  unknown,
  one,
  two,
  three
 };
Q_ENUM(Enum)
};

Now we have another Q_GADGET struct which must be serialized. It contains field MyEnumWrapper::Enum myEnumField; How should Q_PROPERTY and other stuff like getter be organized for QtJsonSerializer? I mean that I'd like to see stringified enum values. I am aware about setEnumAsString(true);.

I am using Qt 5.15.0. I followed the steps in the readme for building the library and sample code from scratch. everything seems to build fine but when I run the sample application I get the follow.
error while loading shared libraries: libQt5JsonSerializer.so.4: cannot open shared object file: No such file or directory
Now i double checked the make files for sample which pointed to the correct path for the library. So I don't know what the issue could be. Any help would be much appreciated. attached is my console ouput for two commands. Also should my bin folder include anything? cause at the moment its empty
makeall_output.txt
makeinstall_output.txt

in my program, i need some kind of type, like QMap<QString, QList<SaleProperty*>>
but no matter what i tried, it always crash

Here is whate i tried:
qRegisterMetaType<QMap<QString, QList<SaleProperty*>>>("QMap<QString, QList<SaleProperty*>>");
qRegisterMetaType<QMap<QString, QStringList>>("QMap<QString, QStringList>");
qRegisterMetaType<QMap<QString, QList>>("QMap<QString, QList>");
QJsonSerializer::registerAllConverters<QList>();
QJsonSerializer::registerMapConverters<QList<SaleProperty*>>();
QJsonSerializer::registerListConverters<SaleProperty*>();

I would be very grateful if you can provide some help.

Hi.
Is it right that one can use std::optional as Q_PROPERTY type, e.g. like following (since 3.4)?

Q_DECLARE_METATYPE(std::optional<int>)
...
QJsonSerializer::registerOptionalConverters<int>();
...

class Test : public QObject {
    Q_OBJECT

    Q_PROPERTY(std::optional<int> type READ type WRITE setType NOTIFY typeChanged)

signals:
    void typeChanged();

public:
    void setType(std::optional<int> type);
    std::optional<int> type() const;

private:
    std::optional<int> m_type;
};

Thank you.

Hello there.
I'm currently using version 3.3.1-3 and I have to keep using that version because I have to use Qt 5.12.4.
The problem as mentioned in the title is that I need to compact my final binary file and also reduce compile time but registering all the converters is taking a lot of resources.
Can you show me a clean way to remove those converters and register only needed ones?

Thanks in advance.

Hello there,
I was trying to deserialize some polymorphic classes which use none-default constructors by creating my own QJsonTypeConverter with the help of discussion about it in issue #22.
let's say we have class Base and class Derived.
I faced a problem with the canConvert() function.
when I want to deserialize the Derived class canConvert() is called with the metaTypeId of Base * instead of Derived *.
Am I doing something wrong?
How can I solve that problem?

Hello! I have to use old GCC 4.7.2. Building your project leads to the following errors:
In file included from qjsonserializerexception.cpp:1:0: qjsonserializerexception.h:12:31: error: looser throw specifier for ‘virtual QJsonSerializerException::~QJsonSerializerException()’ In file included from /usr/lib/Qt5.9/include/QtCore/QtCore:56:0, from ../../include/QtJsonSerializer/QtJsonSerializerDepends:3: /usr/lib/Qt5.9/include/QtCore/qexception.h:62:5: error: overriding ‘virtual QException::~QException() noexcept (true)’ make[2]: *** [.obj/qjsonserializerexception.o] Error 1 make[2]: Leaving directory /home/user/QtJsonSerializer/src/jsonserializer'
make[1]: *** [sub-jsonserializer-make_first-ordered] Error 2
make[1]: Leaving directory /home/user/QtJsonSerializer/src' make: *** [sub-src-make_first] Error 2

Tell me please, what is the workaround?

Hello! Is it reasonable to represent QHash<int, QString> field as QVariantHash property (using getter/setter fo conversion)?

I would like to serialise QList<TestObject *> * and QHash<QString,TestObject *> * and i am having a bit of a hard time figuring out how to do it. More specifically i am trying to serialise lists and hashes that are members of a class but have been allocated on the heap instead of the stack. I would appreciate your help.

Awesome library by the way!!!

Hello! Is it possible to use pointer (or QSharedPointer) to Q_GADGET struct/class as a property for serialization in future? Please, see QMetaType::PointerToGadget:
https://git.qt.io/consulting-usa/qtbase-xcb-rendering/commit/30da659af5ff4ee33c22a3fc81801cdcbc57d535
What workaround can be applied in QJsonTypeConverter ancestor? I suppose that I have to use patched QMetaType...