Skip serializing at runtime with `skip_serializing_if`?

July 29, 2023

I read about serde::skip_serializing_if and I would like to iplement it into my project, however I did not find a way to read the value at runtime (imagine a flag --ignore-practices).

I tried with a static value but without success…

See example below.

#[derive(Debug, Clone, PartialEq, Deserialize, Serialize)]
pub struct IP {
    pub name: String,
    #[serde(skip_serializing_if = "read_flag_from_command_line")]
    pub practices: Option<Practices>,
}

fn is_false<T>(_: T) -> bool {
    let ignore = value_at_run_time;
    return ignore;
}

>Solution :

That’s not how skip_serializing_if works or what it’s for, the function given to it has to take the field as a reference and should determine it’s result based on that.

That being said you could write a function that depends on global state to determine if it serializes or not as a hack:

static SERIALIZE_PRACTICES: AtomicBool = AtomicBool::new(false);

fn dont_serialize_practices<T>(_: &T) -> bool {
    !SERIALIZE_PRACTICES.load(Ordering::Acquire)
}
#[derive(Debug, Clone, PartialEq, Deserialize, Serialize)]
pub struct Ip {
    #[serde(skip_serializing_if = "dont_serialize_practices")]
    pub practices: Option<String>,
}

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