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use crate::error::Error as GoogleMapsError;
use crate::request_rate::api::Api;
use crate::roads::error::Error as RoadsError;
use crate::roads::snap_to_roads::{
request::Request as SnapToRoadsRequest, response::Response as SnapToRoadsResponse, SERVICE_URL,
};
use backoff::future::retry;
use backoff::Error::{Permanent, Transient};
use backoff::ExponentialBackoff;
// -----------------------------------------------------------------------------
impl<'a> SnapToRoadsRequest<'a> {
/// Performs the HTTP get request and returns the response to the caller.
///
/// ## Arguments
///
/// This method accepts no arguments.
#[tracing::instrument(level = "debug", name = "google_maps.snap_to_roads", skip(self))]
pub async fn get(&mut self) -> Result<SnapToRoadsResponse, GoogleMapsError> {
// Build the URL stem for the HTTP get request:
let mut url = format!("{SERVICE_URL}/?");
match &self.query {
// If query string built, append it to the URL stem.
Some(query) => url.push_str(query.as_ref()),
// If query string not built, return an error.
None => return Err(RoadsError::QueryNotBuilt)?,
} // match
// Observe any rate limiting before executing request:
self.client
.rate_limit
.limit_apis(vec![&Api::All, &Api::Roads])
.await;
// Emit debug message so client can monitor activity:
tracing::debug!("Making HTTP GET request to Google Maps Roads API: `{url}`");
// Retries the get request until successful, an error ineligible for
// retries is returned, or we have reached the maximum retries. Note:
// errors wrapped in `Transient()` will retried by the `backoff` crate
// while errors wrapped in `Permanent()` will exit the retry loop.
let response = retry(ExponentialBackoff::default(), || async {
// Query the Google Cloud Maps Platform using using an HTTP get
// request, and return result to caller:
let response = self.client.get_request(&url).await;
// Check response from the HTTP client:
match response {
Ok(response) => {
// HTTP client was successful getting a response from the
// server. Check the HTTP status code:
if response.status().is_success() {
// If the HTTP GET request was successful, get the
// response text:
let text = &response.text().await;
match text {
Ok(text) => {
match serde_json::from_str::<SnapToRoadsResponse>(text) {
Ok(deserialized) => {
// Google API returned an error. This
// indicates an issue with the request.
// In most cases, retrying will not
// help:
if let Some(error) = deserialized.error {
let error = RoadsError::GoogleMapsService(
error.status.clone(),
Some(error.message),
);
tracing::error!("{}", error);
Err(Permanent(error))
// If the response JSON was successfully
// parsed, check the Google API status
// before returning it to the caller:
} else {
// If Google's response did not
// contain an `ErrorResponse`
// struct, return the struct
// deserialized from JSON:
Ok(deserialized)
} // if
} // Ok(deserialized)
Err(error) => {
tracing::error!("JSON parsing error: {}", error);
Err(Permanent(RoadsError::SerdeJson(error)))
} // Err
} // match
} // Ok(text)
Err(error) => {
tracing::error!("HTTP client returned: {}", error);
Err(Permanent(RoadsError::ReqwestMessage(error.to_string())))
} // Err
} // match
// We got a response from the server but it was not OK.
// Only HTTP "500 Server Errors", and HTTP "429 Too Many
// Requests" are eligible for retries.
} else if response.status().is_server_error() || response.status() == 429 {
tracing::warn!("HTTP client returned: {}", response.status());
Err(Transient {
err: RoadsError::HttpUnsuccessful(response.status().to_string()),
retry_after: None,
})
// Not a 500 Server Error or "429 Too Many Requests" error.
// The error is permanent, do not retry:
} else {
tracing::error!("HTTP client returned: {}", response.status());
Err(Permanent(RoadsError::HttpUnsuccessful(
response.status().to_string(),
)))
} // if
} // case
// HTTP client did not get a response from the server. Retry:
Err(error) => {
tracing::warn!("HTTP client returned: {}", error);
Err(Transient {
err: RoadsError::Reqwest(error),
retry_after: None,
})
} // case
} // match
})
.await?;
// Return response to caller:
Ok(response)
} // fn
} // impl