lando 0.2.1

Rust http interface for AWS lambda API gateway events
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//! Response types

// Std
use std::ops::Not;

use http::header::{HeaderMap, HeaderValue};
use http::Response as HttpResponse;
use serde::{ser::Error as SerError, ser::SerializeMap, Serializer};

use body::Body;

/// Representation of API Gateway response
#[derive(Serialize, Debug)]
#[serde(rename_all = "camelCase")]
pub(crate) struct GatewayResponse {
    pub status_code: u16,
    #[serde(
        skip_serializing_if = "HeaderMap::is_empty",
        serialize_with = "serialize_headers"
    )]
    pub headers: HeaderMap<HeaderValue>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub body: Option<Body>,
    #[serde(skip_serializing_if = "Not::not")]
    pub is_base64_encoded: bool,
}

impl Default for GatewayResponse {
    fn default() -> Self {
        Self {
            status_code: 200,
            headers: Default::default(),
            body: Default::default(),
            is_base64_encoded: Default::default(),
        }
    }
}

fn serialize_headers<S>(headers: &HeaderMap<HeaderValue>, serializer: S) -> Result<S::Ok, S::Error>
where
    S: Serializer,
{
    let mut map = serializer.serialize_map(Some(headers.keys_len()))?;
    for key in headers.keys() {
        let map_value = headers[key].to_str().map_err(S::Error::custom)?;
        map.serialize_entry(key.as_str(), map_value)?;
    }
    map.end()
}

impl<T> From<HttpResponse<T>> for GatewayResponse
where
    T: Into<Body>,
{
    fn from(value: HttpResponse<T>) -> Self {
        let (parts, bod) = value.into_parts();
        let (is_base64_encoded, body) = match bod.into() {
            Body::Empty => (false, None),
            b @ Body::Text(_) => (false, Some(b)),
            b @ Body::Binary(_) => (true, Some(b)),
        };
        GatewayResponse {
            status_code: parts.status.as_u16(),
            body,
            headers: parts.headers,
            is_base64_encoded,
        }
    }
}

#[cfg(test)]
mod tests {

    use super::GatewayResponse;
    use serde_json;

    #[test]
    fn default_response() {
        assert_eq!(GatewayResponse::default().status_code, 200)
    }

    #[test]
    fn serialize_default() {
        assert_eq!(
            serde_json::to_string(&GatewayResponse::default())
                .expect("failed to serialize response"),
            r#"{"statusCode":200}"#
        );
    }

    #[test]
    fn serialize_body() {
        let mut resp = GatewayResponse::default();
        resp.body = Some("foo".into());
        assert_eq!(
            serde_json::to_string(&resp).expect("failed to serialize response"),
            r#"{"statusCode":200,"body":"foo"}"#
        );
    }
}