Struct JsonObject

Source

pub struct JsonObject { /* private fields */ }

Expand description

A JSON object: members in insertion order with unique keys.

Keys are guaranteed unique — the parser rejects duplicates, and insert replaces an existing key in place rather than adding a second entry. Lookup is linear; object size is bounded by JsonLimits when parsing untrusted input.

Implementations§

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impl JsonObject

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pub fn get_str_as<'a, T>(&'a self, key: &str) -> Result<T, JsonExtractError>
where T: TryFrom<&'a str, Error = PrimitiveError>,

Extracts member key as a string-backed primitive T, validating it through T’s TryFrom<&str> constructor.

Returns JsonExtractErrorKind::Missing if the key is absent, JsonExtractErrorKind::WrongType if the member is not a JSON string, and JsonExtractErrorKind::Invalid (wrapping the PrimitiveError) if the string fails validation. The error carries the $.key path.

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impl JsonObject

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pub fn new() -> Self

Creates an empty object.

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pub fn get(&self, key: &str) -> Option<&JsonValue>

Returns the value for key, if present.

Examples found in repository ?

examples/basic.rs (line 23)

9fn main() {
10    // Treat this as untrusted input: parse under a conservative limit profile.
11    let input = r#"{ "service": "api", "port": 8080, "tags": ["a", "b"], "enabled": true }"#;
12    let limits = JsonLimits::conservative();
13
14    let value = match parse_with_limits(input.as_bytes(), limits) {
15        Ok(value) => value,
16        Err(err) => {
17            eprintln!("rejected: {err}");
18            return;
19        }
20    };
21
22    if let JsonValue::Object(object) = &value {
23        if let Some(port) = object.get("port").and_then(JsonValue::as_number) {
24            println!("port = {}", port.to_u64().unwrap());
25        }
26        if let Some(tags) = object.get("tags").and_then(JsonValue::as_array) {
27            println!("tags = {}", tags.len());
28        }
29    }
30
31    // Deterministic, member-order-preserving serialization.
32    println!("compact = {}", to_compact_string(&value));
33
34    // Strict by default: these are all rejected.
35    for bad in [r#"{"a":1,"a":2}"#, "{ /* c */ }", "[1,]", "NaN"] {
36        match parse_with_limits(bad.as_bytes(), limits) {
37            Ok(_) => println!("accepted (unexpected): {bad}"),
38            Err(err) => println!("rejected {bad:?}: {}", err.kind_str()),
39        }
40    }
41}

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pub fn contains_key(&self, key: &str) -> bool

Returns true if key is present.

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pub fn insert(&mut self, key: String, value: JsonValue) -> Option<JsonValue>

Inserts or replaces key. If the key already exists its value is replaced in place (preserving position) and the old value is returned; otherwise the member is appended.

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