1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353

//! ALB and API Gateway extension methods for `http::Request` types

use failure::Fail;
use http::{header::CONTENT_TYPE, Request as HttpRequest};
use serde::{de::value::Error as SerdeError, Deserialize};
use serde_json;
use serde_urlencoded;

use crate::{request::RequestContext, strmap::StrMap};

/// ALB/API gateway pre-parsed http query string parameters
pub(crate) struct QueryStringParameters(pub(crate) StrMap);

/// API gateway pre-extracted url path parameters
///
/// These will always be empty for ALB requests
pub(crate) struct PathParameters(pub(crate) StrMap);

/// API gateway configured
/// [stage variables](https://docs.aws.amazon.com/apigateway/latest/developerguide/stage-variables.html)
///
/// These will always be empty for ALB requests
pub(crate) struct StageVariables(pub(crate) StrMap);

/// Payload deserialization errors
#[derive(Debug, Fail)]
pub enum PayloadError {
    /// Returned when `application/json` bodies fail to deserialize a payload
    #[fail(display = "failed to parse payload from application/json")]
    Json(serde_json::Error),
    /// Returned when `application/x-www-form-urlencoded` bodies fail to deserialize a payload
    #[fail(display = "failed to parse payload application/x-www-form-urlencoded")]
    WwwFormUrlEncoded(SerdeError),
}

/// Extentions for `lambda_http::Request` structs that
/// provide access to [API gateway](https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-input-format)
/// and [ALB](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html)
/// features.
///
/// # Examples
///
/// You can also access a request's body in deserialized format
/// for payloads sent in `application/x-www-form-urlencoded` or
/// `application/json` format.
///
/// The following handler will work an http request body of `x=1&y=2`
/// as well as `{"x":1, "y":2}` respectively.
///
/// ```rust,no_run
/// use lambda_runtime::{Context, error::HandlerError};
/// use lambda_http::{lambda, Body, Request, Response, RequestExt};
/// use serde_derive::Deserialize;
///
/// #[derive(Debug,Deserialize,Default)]
/// struct Args {
///   #[serde(default)]
///   x: usize,
///   #[serde(default)]
///   y: usize
/// }
///
/// fn main() {
///   lambda!(handler)
/// }
///
/// fn handler(
///   request: Request,
///   ctx: Context
/// ) -> Result<Response<Body>, HandlerError> {
///   let args: Args = request.payload()
///     .unwrap_or_else(|_parse_err| None)
///     .unwrap_or_default();
///   Ok(
///      Response::new(
///        format!(
///          "{} + {} = {}",
///          args.x,
///          args.y,
///          args.x + args.y
///        ).into()
///      )
///   )
/// }
/// ```
pub trait RequestExt {
    /// Return pre-parsed http query string parameters, parameters
    /// provided after the `?` portion of a url,
    /// associated with the API gateway request.
    ///
    /// The yielded value represents both single and multi-valued
    /// parameters alike. When multiple query string parameters with the same
    /// name are expected, `query_string_parameters().get_all("many")` to retrieve them all.
    ///
    /// No query parameters
    /// will yield an empty `StrMap`.
    fn query_string_parameters(&self) -> StrMap;

    /// Configures instance with query string parameters under #[cfg(test)] configurations
    ///
    /// This is intended for use in mock testing contexts.
    #[cfg(test)]
    fn with_query_string_parameters<Q>(self, parameters: Q) -> Self
    where
        Q: Into<StrMap>;

    /// Return pre-extracted path parameters, parameter provided in url placeholders
    /// `/foo/{bar}/baz/{boom}`,
    /// associated with the API gateway request. No path parameters
    /// will yield an empty `StrMap`
    ///
    /// These will always be empty for ALB triggered requests
    fn path_parameters(&self) -> StrMap;

    /// Configures instance with path parameters under #[cfg(test)] configurations
    ///
    /// This is intended for use in mock testing contexts.
    #[cfg(test)]
    fn with_path_parameters<P>(self, parameters: P) -> Self
    where
        P: Into<StrMap>;

    /// Return [stage variables](https://docs.aws.amazon.com/apigateway/latest/developerguide/stage-variables.html)
    /// associated with the API gateway request. No stage parameters
    /// will yield an empty `StrMap`
    ///
    /// These will always be empty for ALB triggered requests
    fn stage_variables(&self) -> StrMap;

    /// Configures instance with stage variables under #[cfg(test)] configurations
    ///
    /// This is intended for use in mock testing contexts.
    #[cfg(test)]
    fn with_stage_variables<V>(self, variables: V) -> Self
    where
        V: Into<StrMap>;

    /// Return request context data assocaited with the ALB or API gateway request
    fn request_context(&self) -> RequestContext;

    /// Return the Result of a payload parsed into a serde Deserializeable
    /// type
    ///
    /// Currently only `application/x-www-form-urlencoded`
    /// and `application/json` flavors of content type
    /// are supported
    ///
    /// A [PayloadError](enum.PayloadError.html) will be returned for undeserializable
    /// payloads. If no body is provided, `Ok(None)` will be returned.
    fn payload<D>(&self) -> Result<Option<D>, PayloadError>
    where
        for<'de> D: Deserialize<'de>;
}

impl RequestExt for HttpRequest<super::Body> {
    fn query_string_parameters(&self) -> StrMap {
        self.extensions()
            .get::<QueryStringParameters>()
            .map(|ext| ext.0.clone())
            .unwrap_or_default()
    }

    #[cfg(test)]
    fn with_query_string_parameters<Q>(self, parameters: Q) -> Self
    where
        Q: Into<StrMap>,
    {
        let mut s = self;
        s.extensions_mut().insert(QueryStringParameters(parameters.into()));
        s
    }

    fn path_parameters(&self) -> StrMap {
        self.extensions()
            .get::<PathParameters>()
            .map(|ext| ext.0.clone())
            .unwrap_or_default()
    }

    #[cfg(test)]
    fn with_path_parameters<P>(self, parameters: P) -> Self
    where
        P: Into<StrMap>,
    {
        let mut s = self;
        s.extensions_mut().insert(PathParameters(parameters.into()));
        s
    }

    fn stage_variables(&self) -> StrMap {
        self.extensions()
            .get::<StageVariables>()
            .map(|ext| ext.0.clone())
            .unwrap_or_default()
    }

    #[cfg(test)]
    fn with_stage_variables<V>(self, variables: V) -> Self
    where
        V: Into<StrMap>,
    {
        let mut s = self;
        s.extensions_mut().insert(StageVariables(variables.into()));
        s
    }

    fn request_context(&self) -> RequestContext {
        self.extensions().get::<RequestContext>().cloned().unwrap_or_default()
    }

    fn payload<D>(&self) -> Result<Option<D>, PayloadError>
    where
        for<'de> D: Deserialize<'de>,
    {
        self.headers()
            .get(CONTENT_TYPE)
            .map(|ct| match ct.to_str() {
                Ok("application/x-www-form-urlencoded") => serde_urlencoded::from_bytes::<D>(self.body().as_ref())
                    .map_err(PayloadError::WwwFormUrlEncoded)
                    .map(Some),
                Ok("application/json") => serde_json::from_slice::<D>(self.body().as_ref())
                    .map_err(PayloadError::Json)
                    .map(Some),
                _ => Ok(None),
            })
            .unwrap_or_else(|| Ok(None))
    }
}

#[cfg(test)]
mod tests {
    use http::{HeaderMap, Request as HttpRequest};
    use serde_derive::Deserialize;
    use std::collections::HashMap;

    use crate::{LambdaRequest, Request, RequestExt, StrMap};

    #[test]
    fn requests_can_mock_query_string_parameters_ext() {
        let mocked = hashmap! {
            "foo".into() => vec!["bar".into()]
        };
        let request = Request::default().with_query_string_parameters(mocked.clone());
        assert_eq!(request.query_string_parameters(), mocked.into());
    }

    #[test]
    fn requests_can_mock_path_parameters_ext() {
        let mocked = hashmap! {
            "foo".into() => vec!["bar".into()]
        };
        let request = Request::default().with_path_parameters(mocked.clone());
        assert_eq!(request.path_parameters(), mocked.into());
    }

    #[test]
    fn requests_can_mock_stage_variables_ext() {
        let mocked = hashmap! {
            "foo".into() => vec!["bar".into()]
        };
        let request = Request::default().with_stage_variables(mocked.clone());
        assert_eq!(request.stage_variables(), mocked.into());
    }

    #[test]
    fn requests_have_query_string_ext() {
        let mut headers = HeaderMap::new();
        headers.insert("Host", "www.rust-lang.org".parse().unwrap());
        let mut query = HashMap::new();
        query.insert("foo".to_owned(), vec!["bar".to_owned()]);
        let lambda_request = LambdaRequest {
            path: "/foo".into(),
            headers,
            query_string_parameters: StrMap(query.clone().into()),
            ..LambdaRequest::default()
        };
        let actual = HttpRequest::from(lambda_request);
        assert_eq!(actual.query_string_parameters(), StrMap(query.clone().into()));
    }

    #[test]
    fn requests_have_form_post_parseable_payloads() {
        let mut headers = HeaderMap::new();
        headers.insert("Host", "www.rust-lang.org".parse().unwrap());
        headers.insert("Content-Type", "application/x-www-form-urlencoded".parse().unwrap());
        #[derive(Deserialize, PartialEq, Debug)]
        struct Payload {
            foo: String,
            baz: usize,
        }
        let lambda_request = LambdaRequest {
            path: "/foo".into(),
            headers,
            body: Some("foo=bar&baz=2".into()),
            ..LambdaRequest::default()
        };
        let actual = HttpRequest::from(lambda_request);
        let payload: Option<Payload> = actual.payload().unwrap_or_default();
        assert_eq!(
            payload,
            Some(Payload {
                foo: "bar".into(),
                baz: 2
            })
        )
    }

    #[test]
    fn requests_have_form_post_parseable_payloads_for_hashmaps() {
        let mut headers = HeaderMap::new();
        headers.insert("Host", "www.rust-lang.org".parse().unwrap());
        headers.insert("Content-Type", "application/x-www-form-urlencoded".parse().unwrap());
        let lambda_request = LambdaRequest {
            path: "/foo".into(),
            headers,
            body: Some("foo=bar&baz=2".into()),
            ..LambdaRequest::default()
        };
        let actual = HttpRequest::from(lambda_request);
        let mut expected = HashMap::new();
        expected.insert("foo".to_string(), "bar".to_string());
        expected.insert("baz".to_string(), "2".to_string());
        let payload: Option<HashMap<String, String>> = actual.payload().unwrap_or_default();
        assert_eq!(payload, Some(expected))
    }

    #[test]
    fn requests_have_json_parseable_payloads() {
        let mut headers = HeaderMap::new();
        headers.insert("Host", "www.rust-lang.org".parse().unwrap());
        headers.insert("Content-Type", "application/json".parse().unwrap());
        #[derive(Deserialize, PartialEq, Debug)]
        struct Payload {
            foo: String,
            baz: usize,
        }
        let lambda_request: LambdaRequest<'_> = LambdaRequest {
            path: "/foo".into(),
            headers,
            body: Some(r#"{"foo":"bar", "baz": 2}"#.into()),
            ..LambdaRequest::default()
        };
        let actual = HttpRequest::from(lambda_request);
        let payload: Option<Payload> = actual.payload().unwrap_or_default();
        assert_eq!(
            payload,
            Some(Payload {
                foo: "bar".into(),
                baz: 2
            })
        )
    }
}