read and write to Json files

Added by Malin Edvardsen almost 12 years ago

Hello there Wt folks!

So, as you might guess form the title, yes I am not to good at this :P I have tried to figure out how to do this from the wt documentation, but I am not quite sure if I am doing things correctly or not. What I want (or a simplified explanation of what I need) is to be able to read data from a json file, put some of the results into a editable table and then be able to write the contents of that table back to the json files again.

My idea was then to make a class like this:

JsonFile.h

class JsonFile : public Wt::WResource {
public:
    JsonFile(const Wt::WString & fileName);
    virtual ~JsonFile();

protected:
    Wt::Json::Object jsonObject;

    void handleRequest(const Wt::Http::Request& request,
            Wt::Http::Response& response);
};

JsonFile.cpp

JsonFile::JsonFile(const Wt::WString & fileName)
{
    suggestFileName(fileName);
}

JsonFile::~JsonFile()
{
    beingDeleted();
}

void JsonFile::handleRequest(const Wt::Http::Request& request,
        Wt::Http::Response& response)
{
    Wt::Json::parse(??????,
            jsonObject);
}

Then I will later have different classes that inherit JsonFile and that will organize the content into the table depending on the class type. Am I no the right track of something here?

Now, as you might see, the part where I get a bit confused is the handleRequest function.. I did see the examples here http://www.webtoolkit.eu/wt/doc/reference/html/classWt_1_1WResource.html

but I guess I am just not clever enough to make a lot of sense out of it. How should I use it, how should I call it? (yes I know there is a lot of issues with several people using the app at the same time, reading and writing to these files, but I have plans on how to handle that issue, required login and separate git branches included in these plans). So if someone could help me in the right direction here, I would be trilled!

Regards, new Wt user

Malin

Replies (2)

RE: read and write to Json files - Added by Malin Edvardsen almost 12 years ago

Or might I be wrong using WResource for this, and should instead just use std::ifstream?

RE: read and write to Json files - Added by Koen Deforche almost 12 years ago

Hey,

Our json interface probably should be extended to allow reading from an std::istream too.

But the following can help you in the mean time:

std::ifstream f("file.json");
std::istreambuf_iterator<char> eos;
std::string s(std::istreambuf_iterator<char>(f), eos);

Wt::Json::Object o;
Wt::Json::ParseError e;
if (Wt::Json::parse(response.body(), o, e)) {
  ...
}

Note, writing out JSon is a feature request currently pending in our tracker.

Regards,

koen

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