Probleme mit immer ein Knoten aus der JSON mit jsoncpp

Ich versuche zu verwenden jsoncpp zu analysieren, eine Reihe von json. Die json generiert wurde, von einer Webseite mit simplejson aus einem django-Objekt. Ich bekomme es aus eine bestimmte URL mit Hilfe von libcurl. Wenn ich den toStyledString () - Funktion auf dem root bekomme ich diese ausgedruckt.

[
   {
      "fields" : {
         "desc" : "Carol King test",
         "format" : "1",
         "genre" : "Pop",
         "mount" : "CarolKing",
         "name" : "Carol King",
         "protocol" : "0",
         "songs" : [ 27, 28, 29, 30, 31, 32, 33, 34 ],
         "url" : "http://192.168.0.5:8000/CarolKing"
      },
      "model" : "music.playlist",
      "pk" : 2
   }
]

So, wie es scheint, bin ich immer die richtigen Daten und die in einer Json::Wert-Klasse.

Das problem ist, dass ich nicht in der Lage zu einem bestimmten Knoten aus der json-Struktur. Dies ist der code im Einsatz.

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <sstream>
#include <curl/curl.h>
#include <string>
#include "Parameter.h"
#include "lib_json/json.h"

using namespace std;

static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream)
{
    cout << "-->write_data " << endl;
    string buf = string(static_cast<char *>(ptr), size *nmemb);
    stringstream * response = static_cast<stringstream *>(stream);
    response->write(buf.c_str(), (streamsize)buf.size());
    return size * nmemb;

}


int main(int sys_argc, char ** sys_argv) {
    CURL *curl;
    CURLcode res;
    stringstream response;
    string error;

    char ** argv = sys_argv;


    string file = argv[1];
    Parameter *parms = new Parameter(file);
    parms->ReadParameters();

    cout << "URL: " << parms->GetParameter("URL");


    curl_global_init(CURL_GLOBAL_ALL);
    curl = curl_easy_init();
    if(curl)
    {
        curl_easy_setopt(curl, CURLOPT_URL, parms->GetParameter("URL").c_str());
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);
        res = curl_easy_perform(curl);

        cout << "Playlists-JSON: " << response.str() << endl;
        curl_easy_cleanup(curl);
    }

    Json::Value root;
    Json::Reader reader;

    bool parsingSuccessful = reader.parse(response.str(), root);

    if(!parsingSuccessful)
    {
        cout << "Failed to parse configuration. " << reader.getFormatedErrorMessages();
        return 16;
    }

    cout << "Pretty-Print: " << root.toStyledString() << endl;
    const Json::Value fields = root["fields"]["songs"];


    return 0;
}

wegen einem anderen Problem, ich bin nicht mit der tatsächlichen libjson.so shared library, im nur ziehen in den Dateien, und kompilieren Sie Sie in mit meiner Hand (ich vermute, das ist schlecht, aber das problem ist nicht der Punkt dieser Frage). Unten ist, wie mein src Ordner strukturiert ist.

.:
bird  Bird.cpp  fopen.cpp  fopen.h  lib_json  Parameter.cpp  Parameter.h

./lib_json:
autolink.h  features.h  json_batchallocator.h  json_internalarray.inl  json_reader.cpp  json_valueiterator.inl  reader.h    value.h
config.h    forwards.h  json.h                 json_internalmap.inl    json_value.cpp   json_writer.cpp         sconscript  writer.h

- und dies ist die Ausgabe stellen.

    munderwo@bertha:/local/Documents/inthebackground/Box/Bird/bird/Debug$ make
Building file: ../src/lib_json/json_reader.cpp
Invoking: GCC C++ Compiler
g++ -I"/local/Documents/inthebackground/Box/Bird/bird/Libraries/i386/include" -I"/local/Documents/inthebackground/Box/Bird/bird/src" -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/lib_json/json_reader.d" -MT"src/lib_json/json_reader.d" -o"src/lib_json/json_reader.o" "../src/lib_json/json_reader.cpp"
Finished building: ../src/lib_json/json_reader.cpp

Building file: ../src/lib_json/json_value.cpp
Invoking: GCC C++ Compiler
g++ -I"/local/Documents/inthebackground/Box/Bird/bird/Libraries/i386/include" -I"/local/Documents/inthebackground/Box/Bird/bird/src" -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/lib_json/json_value.d" -MT"src/lib_json/json_value.d" -o"src/lib_json/json_value.o" "../src/lib_json/json_value.cpp"
Finished building: ../src/lib_json/json_value.cpp

Building file: ../src/lib_json/json_writer.cpp
Invoking: GCC C++ Compiler
g++ -I"/local/Documents/inthebackground/Box/Bird/bird/Libraries/i386/include" -I"/local/Documents/inthebackground/Box/Bird/bird/src" -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/lib_json/json_writer.d" -MT"src/lib_json/json_writer.d" -o"src/lib_json/json_writer.o" "../src/lib_json/json_writer.cpp"
Finished building: ../src/lib_json/json_writer.cpp

Building file: ../src/Bird.cpp
Invoking: GCC C++ Compiler
g++ -I"/local/Documents/inthebackground/Box/Bird/bird/Libraries/i386/include" -I"/local/Documents/inthebackground/Box/Bird/bird/src" -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/Bird.d" -MT"src/Bird.d" -o"src/Bird.o" "../src/Bird.cpp"
Finished building: ../src/Bird.cpp

Building file: ../src/Parameter.cpp
Invoking: GCC C++ Compiler
g++ -I"/local/Documents/inthebackground/Box/Bird/bird/Libraries/i386/include" -I"/local/Documents/inthebackground/Box/Bird/bird/src" -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/Parameter.d" -MT"src/Parameter.d" -o"src/Parameter.o" "../src/Parameter.cpp"
../src/Parameter.cpp: In member function ‘int Parameter::ReadParameters()’:
../src/Parameter.cpp:47: warning: comparison between signed and unsigned integer expressions
Finished building: ../src/Parameter.cpp

Building file: ../src/fopen.cpp
Invoking: GCC C++ Compiler
g++ -I"/local/Documents/inthebackground/Box/Bird/bird/Libraries/i386/include" -I"/local/Documents/inthebackground/Box/Bird/bird/src" -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/fopen.d" -MT"src/fopen.d" -o"src/fopen.o" "../src/fopen.cpp"
Finished building: ../src/fopen.cpp

Building target: Bird
Invoking: GCC C++ Linker
g++ -L"/local/Documents/inthebackground/Box/Bird/bird/Libraries/i386/lib" -o"Bird"  ./src/lib_json/json_reader.o ./src/lib_json/json_value.o ./src/lib_json/json_writer.o  ./src/Bird.o ./src/Parameter.o ./src/fopen.o   -lcurl
Finished building target: Bird

und von allen, die ich bekomme folgende Ausgabe, wenn ich ausführen Vogel

*Bird: ../src/lib_json/json_value.cpp:1025: Json::Value& Json::Value::resolveReference(const char*, bool): Assertion `type_ == nullValue || type_ == objectValue' failed.*
URL: 127.0.0.1:8000/playlist-->write_data 
Playlists-JSON: [{"pk": 2, "model": "music.playlist", "fields": {"protocol": "0", "name": "Carol King", "format": "1", "url": "http://192.168.0.5:8000/CarolKing", "mount": "CarolKing", "genre": "Pop", "songs": [27, 28, 29, 30, 31, 32, 33, 34], "desc": "Carol King test"}}]
Pretty-Print: [
   {
      "fields" : {
         "desc" : "Carol King test",
         "format" : "1",
         "genre" : "Pop",
         "mount" : "CarolKing",
         "name" : "Carol King",
         "protocol" : "0",
         "songs" : [ 27, 28, 29, 30, 31, 32, 33, 34 ],
         "url" : "http://192.168.0.5:8000/CarolKing"
      },
      "model" : "music.playlist",
      "pk" : 2
   }
]

Ich nicht das problem, wenn ich diese Zeile auskommentieren

const Json::Value fields = root["songs"];

Im Total offen für die Tatsache, dass ich etwas falsch hier. Aber ich weiß nur nicht, was es ist. So, was den Fehler verursacht:

Bird: ../src/lib_json/json_value.cpp:1025: Json::Value& Json::Value::resolveReference(const char*, bool): Assertion `type_ == nullValue || type_ == objectValue' failed.

vielen Dank für jede Hilfe, die Sie geben können.

Cheers

Mark

InformationsquelleAutor Mark Lakewood | 2010-12-14