Module djson

Example

import djson;

@JSON struct Profile {        // all public fields are bound
    string name;
    string[] tags;
    @JSONOptional int age;    // keeps its init value if missing
}

void main() {
    // Lazy: only the parts you access are parsed (parseJSONComplete parses everything at once)
    auto json = parseJSON(`{
        "user": {
            "id": 123,
            "profile": { "name": "Alice", "tags": ["admin", "beta"] }
        },
        "orders": [ { "total": 9.5 }, { "total": 20 } ]
    }`);

    // 1. Read deep values (variadic or JSON pointer), or a default if missing
    string name = json.get!string("user", "profile", "name");
    string tag0 = json.get!string("/user/profile/tags/0");
    long   karma = json.safe!long("user", "karma").or(0);

    // 2. Check if a key or path exists
    if (json.has("user", "profile", "name")) { /* ... */ }
    bool hasEmail = json.has("/user/contact/email"); // false

    // 3. Iterate objects and arrays
    foreach (string key, ref value; json["user"]) { /* "id", "profile" */ }
    foreach (size_t i, ref order; json["orders"]) { /* ... */ }

    // 4. Query with JSONPath: results are references, editable in place
    double sum = 0;
    foreach (ref total; json.select("$.orders[*].total")) sum += total.get!double;

    // 5. Bind to D types and back
    Profile p = fromJSON!Profile(json["user"]["profile"]);
    JValue pj = toJSON(p);

    // 6. Set or update values (auto-vivifies missing nodes) and build new ones
    json.set("alice@example.com", "user", "contact", "email");
    json.set(1, "/meta/version");
    json["orders"] ~= JSOB("total", 5, "items", JSAB("pen", "ink"));

    // 7. Delete a value or a whole branch
    json["user"]["profile"].remove("tags");
    json.remove("meta");

    // 8. Serialize back to JSON
    string result = json.toJSON(true); // pretty print
}

To read large documents in a single pass without building a tree, see walkJSON. For truncated input arriving from a stream, see JValue.appendData.

See Also

djson.value, djson.parser, djson.jsonpath, djson.walk, djson.binding, djson.builder