Skip downloading files with no plugins

Can determine if file contains plugin by recursively walking the file metadata listing until a .esp/.esm/.esl is found.

src/main.rs

@@ -189,7 +189,16 @@ pub async fn main() -> Result<()> {
                 )
                 .await?;
 
-                // TODO: check the file metadata to see if there are any plugin files in the archive before bothering to download the file (checking metadata does not count against rate-limit)
+                if let Some(contains_plugin) =
+                    nexus_api::metadata::contains_plugin(&client, &api_file).await?
+                {
+                    if !contains_plugin {
+                        info!("file metadata does not contain a plugin, skip downloading");
+                        continue;
+                    }
+                } else {
+                    warn!("file has no metadata link");
+                }
 
                 let download_link_resp =
                     nexus_api::download_link::get(&client, db_mod.nexus_mod_id, api_file.file_id)

src/nexus_api/files.rs

@@ -20,6 +20,7 @@ pub struct ApiFile<'a> {
     pub version: Option<&'a str>,
     pub mod_version: Option<&'a str>,
     pub size: i64,
+    pub content_preview_link: Option<&'a str>,
     pub uploaded_at: NaiveDateTime,
 }
 
@@ -89,6 +90,10 @@ impl FilesResponse {
                     .get("size_in_bytes")
                     .ok_or_else(|| anyhow!("Missing size_in_bytes key in file in API response"))?
                     .as_i64();
+                let content_preview_link = file
+                    .get("content_preview_link")
+                    .ok_or_else(|| anyhow!("Missing content_preview_link key in file in API response"))?
+                    .as_str();
                 let size = if let Some(size) = size {
                     size
                 } else {
@@ -120,6 +125,7 @@ impl FilesResponse {
                     version,
                     mod_version,
                     size,
+                    content_preview_link,
                     uploaded_at,
                 })
             })

src/nexus_api/metadata.rs

@@ -0,0 +1,64 @@
+use anyhow::{anyhow, Result};
+use reqwest::Client;
+use serde_json::Value;
+use std::env;
+use tracing::{info, instrument};
+
+use super::files::ApiFile;
+use super::USER_AGENT;
+
+fn has_plugin(json: &Value) -> Result<bool> {
+    let node_type = json
+        .get("type")
+        .ok_or_else(|| anyhow!("Missing type key in metadata API response"))?
+        .as_str()
+        .ok_or_else(|| anyhow!("type value in metadata is not a string"))?;
+
+    if node_type == "file" {
+        let name = json
+            .get("name")
+            .ok_or_else(|| anyhow!("Missing name key in metadata API response"))?
+            .as_str()
+            .ok_or_else(|| anyhow!("name value in metadata is not a string"))?;
+
+        if name.ends_with(".esp") || name.ends_with(".esm") || name.ends_with(".esl") {
+            return Ok(true);
+        }
+    }
+
+    match json.get("children") {
+        None => Ok(false),
+        Some(children) => {
+            let children = children
+                .as_array()
+                .ok_or_else(|| anyhow!("children value in metadata is not an array"))?;
+            for child in children {
+                if has_plugin(child)? {
+                    return Ok(true);
+                }
+            }
+            Ok(false)
+        }
+    }
+}
+
+#[instrument(skip(client, api_file), fields(metadata_link = api_file.content_preview_link.unwrap_or("null")))]
+pub async fn contains_plugin(client: &Client, api_file: &ApiFile<'_>) -> Result<Option<bool>> {
+    if let Some(metadata_link) = api_file.content_preview_link {
+        let res = client
+            .get(metadata_link)
+            .header("accept", "application/json")
+            .header("apikey", env::var("NEXUS_API_KEY")?)
+            .header("user-agent", USER_AGENT)
+            .send()
+            .await?
+            .error_for_status()?;
+
+        info!(status = %res.status(), "fetched file metadata from API");
+        let json = res.json::<Value>().await?;
+
+        Ok(Some(has_plugin(&json)?))
+    } else {
+        Ok(None)
+    }
+}

src/nexus_api/mod.rs

@@ -7,6 +7,7 @@ use tracing::info;
 
 pub mod download_link;
 pub mod files;
+pub mod metadata;
 
 pub static GAME_NAME: &str = "skyrimspecialedition";
 pub const GAME_ID: u32 = 1704;