Modularize scraping and api requests

src/nexus_api/download_link.rs

@@ -0,0 +1,70 @@
+use anyhow::{anyhow, Result};
+use futures::TryStreamExt;
+use reqwest::Client;
+use serde_json::Value;
+use std::{env, time::Duration};
+use tempfile::tempfile;
+use tokio::fs::File;
+use tokio_util::compat::FuturesAsyncReadCompatExt;
+
+use super::{rate_limit_wait_duration, GAME_NAME, USER_AGENT};
+
+pub struct DownloadLinkResponse {
+    pub wait: Option<Duration>,
+    json: Value,
+}
+
+pub async fn get(client: &Client, mod_id: i32, file_id: i64) -> Result<DownloadLinkResponse> {
+    let res = client
+        .get(format!(
+            "https://api.nexusmods.com/v1/games/{}/mods/{}/files/{}/download_link.json",
+            GAME_NAME, mod_id, file_id
+        ))
+        .header("accept", "application/json")
+        .header("apikey", env::var("NEXUS_API_KEY")?)
+        .header("user-agent", USER_AGENT)
+        .send()
+        .await?
+        .error_for_status()?;
+
+    let wait = rate_limit_wait_duration(&res)?;
+    let json = res.json::<Value>().await?;
+
+    Ok(DownloadLinkResponse { wait, json })
+}
+
+impl DownloadLinkResponse {
+    pub fn link<'a>(&'a self) -> Result<&'a str> {
+        let link = self
+            .json
+            .get(0)
+            .ok_or_else(|| anyhow!("Links array in API response is missing first element"))?
+            .get("URI")
+            .ok_or_else(|| anyhow!("Missing URI key in link in API response"))?
+            .as_str()
+            .ok_or_else(|| anyhow!("URI value in API response link is not a string"))?;
+        Ok(link)
+    }
+
+    pub async fn download_file(&self, client: &Client) -> Result<File> {
+        let mut tokio_file = File::from_std(tempfile()?);
+        let res = client
+            .get(self.link()?)
+            .header("apikey", env::var("NEXUS_API_KEY")?)
+            .header("user-agent", USER_AGENT)
+            .send()
+            .await?
+            .error_for_status()?;
+
+        // See: https://github.com/benkay86/async-applied/blob/master/reqwest-tokio-compat/src/main.rs
+        let mut byte_stream = res
+            .bytes_stream()
+            .map_err(|e| futures::io::Error::new(futures::io::ErrorKind::Other, e))
+            .into_async_read()
+            .compat();
+
+        tokio::io::copy(&mut byte_stream, &mut tokio_file).await?;
+
+        return Ok(tokio_file);
+    }
+}