CODEWITHSUNDEEP
c++jsoncasablanca
Paul S Chapman
Paul S Chapman

Reputation: 832

Reading JSON from a file using C++ REST SDK (Casablanca)

I have the following code which should read the contents of a text file and parse it as JSON

            try {
                string_t        importFile = argv[++iArgCounter];           // extract filename
                ifstream_t      f(importFile);                              // filestream of working file
                stringstream_t  s;                                          // string stream for holding JSON read from file
                json::value     v;                                          // JSON read from input file

                iArgCounter++;                                              // increment arg counter
                if (f) {                                                    
                    s << f.rdbuf();                                         // stream results of reading from file stream into string stream
                    f.close();                                              // close the filestream

                    v.parse(s);                                             // parse the resultant string stream.
                }
            }
            catch (web::json::json_exception excep) {
                std::cout << "ERROR Parsing JSON: ";
                std::cout << excep.what();
                break;
            }

And the following test JSON file

[
    {
        "Destinations":
            [
                {
                    "Domain": "127.0.0.1",
                    "Name": "GoogleLogin",
                    "Port": "8090"
                }
            ],
        "Listeners":
            [
                {
                    "Domain": "127.0.0.1",
                    "Name": "LoginRequest",
                    "Port": "8080",
                    "Route": "ProcessLoginRequest"
                }
            ],
        "Name": "LoginProcess",
        "Routes":
            [
            {
                "Name": "ProcessLoginRequest",
                "Rules":
                    [{
                        "DestinationIfTrue": "GoogleLogin",
                        "LeftTerm":
                            {
                                "RuleTermType": 1,
                                "Value": "NETWORK"
                            },
                        "Operator": 2,
                        "RightTerm":
                            {
                                "RuleTermType": 0,
                                "Value": "NETWORK"
                            }
                    }],
                "Transformations": []
            }
            ]
    }
]

The trouble is no matter what the JSON code I get the error 'Line 1, Column 2 Syntax error: Malformed token'. From what I can tell the JSON is correctly formatted with all brackets balanced.

Code is running on 64bit Windows 7.

Anyone got an idea why it thinks this (or how I can convert the stringstream_t to a string and see what it actually reads).

Upvotes: 6

Views: 6748

Answers (3)

Omi
Omi

Reputation: 31

Multiple things could go wrong here

  • Check if the ifstream is able to open the file correctly using the following

    if(!f)
    cerr << "can't open file";

  • If this is the case, check if name of the file and location is correct or not

  • Also replace

    v.parse(s);

    with

    v = json::value::parse(s.str()) /* As parse would take string as input */

Upvotes: 0

friartuck
friartuck

Reputation: 3121

change the line 

v.parse(s);

to

 v = json::value::parse(s)

Upvotes: 4

daewonyoon
daewonyoon

Reputation: 326

  • Could it be that the file is of utf16 encoding?
  • Or check if your json file has BOM (Byte Oder Mark) at the head by opening it with a hex editor.

Upvotes: 1

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