csv_serializer.md

jsoncons::csv::csv_serializer

The csv_serializer class is an instantiation of the basic_csv_serializer class template that uses char as the character type. It implements json_content_handler and supports formatting a JSON value as a CSV file.

csv_serializer is noncopyable and nonmoveable.

Header

#include <jsoncons_ext/csv/csv_serializer.hpp>

Constructors

csv_serializer(std::ostream& os)

Constructs a csv_serializer that is associated with an output stream os. Uses default csv_serializing_options. You must ensure that the output stream exists as long as does csv_serializer, as json_serializer holds a pointer to but does not own this object.

csv_serializer(std::ostream& os,
               const csv_serializing_options& options)

Constructs a csv_serializer that is associated with an output stream os and csv_serializing_options. You must ensure that the output stream exists as long as does csv_serializer, as json_serializer holds a pointer to but does not own this object.

Member functions

Destructor

virtual ~json_serializer()

Examples

Serializing an array of json values to a comma delimted file

JSON input file

[
    ["country_code","name"],
    ["ABW","ARUBA"],
    ["ATF","FRENCH SOUTHERN TERRITORIES, D.R. OF"],
    ["VUT","VANUATU"],
    ["WLF","WALLIS & FUTUNA ISLANDS"]
]

Note

• The third array element has a value that contains a comma, in the CSV file this value will be quoted.

Serializing the comma delimited file with csv_serializer

std::string in_file = "input/countries.json";
std::ifstream is(in_file);

json_decoder<json> decoder;
json_reader reader(is,decoder);
reader.read();
json countries = decoder.get_result();

csv_serializer serializer(std::cout);

countries.dump(serializer);

Output

country_code,name
ABW,ARUBA
ATF,"FRENCH SOUTHERN TERRITORIES, D.R. OF"
VUT,VANUATU
WLF,WALLIS & FUTUNA ISLANDS

Serializing an array of json objects to a tab delimted file

JSON input file

[
    {
        "dept":"sales",
        "employee-name":"Smith, Matthew",
        "employee-no":"00000001",
        "note":"",
        "salary":"150,000.00"
    },
    {
        "dept":"sales",
        "employee-name":"Brown, Sarah",
        "employee-no":"00000002",
        "note":"",
        "salary":"89,000.00"
    },
    {
        "dept":"finance",
        "employee-name":"Oberc, Scott",
        "employee-no":"00000003",
        "salary":"110,000.00"
    },
    {
        "dept":"sales",
        "employee-name":"Scott, Colette",
        "employee-no":"00000004",
        "note":"\"Exemplary\" employee\nDependable, trustworthy",
        "comment":"Team player",
        "salary":"75,000.00"
    }
]

Note

• The names in the first object in the array will be used for the header row of the CSV file
• The fourth object has a note member whose value contains escaped quotes and an escaped new line character, in the CSV file, this value will be quoted, and it will contain a new line character and escaped quotes.

Dump json value to a tab delimited file

std::string in_file = "input/employees.json";
std::ifstream is(in_file);

json_decoder<json> decoder;
csv_serializing_options options;
params.field_delimiter = '\t';

json_reader reader(is,decoder);
reader.read();
json employees = decoder.get_result();

csv_serializer serializer(std::cout,options);

employees.dump(serializer);

Tab delimited output file

dept    employee-name   employee-no     note    salary
sales   Smith, Matthew  00000001                150,000.00
sales   Brown, Sarah    00000002                89,000.00
finance Oberc, Scott    00000003                110,000.00
sales   Scott, Colette  00000004        ""Exemplary"" employee
Dependable, trustworthy 75,000.00

Dump json value to csv file

#include <jsoncons/json.hpp>
#include <jsoncons_ext/csv/csv_serializer.hpp>

using namespace jsoncons;

int main()
{
    const json books = json::parse(R"(
    [
        {
            "title" : "Kafka on the Shore",
            "author" : "Haruki Murakami",
            "price" : 25.17
        },
        {
            "title" : "Women: A Novel",
            "author" : "Charles Bukowski",
            "price" : 12.00
        },
        {
            "title" : "Cutter's Way",
            "author" : "Ivan Passer"
        }
    ]
    )");

    csv_serializing_options options;
    params.column_names("author,title,price");

    csv_serializer serializer(std::cout, options);

    books.dump(serializer);
}

Output:

author,title,price
Haruki Murakami,Kafka on the Shore,25.17
Charles Bukowski,Women: A Novel,12.0
Ivan Passer,Cutter's Way,