Add shared HTTP client with connection pooling (#41)

* Add shared HTTP client with connection pooling

Previously every request created a new reqwest::Client via Client::new(),
which meant zero connection reuse. Now ChatClient, EmbeddingsClient,
FilesClient, and BatchClient all share a pooled reqwest::Client configured
with pool_max_idle_per_host=256 and pool_idle_timeout=300s.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Bump version to 0.16.0

Breaking change: added http_client field to ChatClient, EmbeddingsClient,
FilesClient, and BatchClient.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: anchpop

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "tysm"
-version = "0.15.0"
+version = "0.16.0"
 edition = "2021"
 description = "Batteries-included Rust OpenAI Client"
 license = "MIT"

Cargo.toml

@@ -35,6 +35,8 @@ pub struct BatchClient {
     pub model: String,
     /// The client to use for file operations.
     pub files_client: FilesClient,
+    /// Shared HTTP client with connection pooling
+    pub http_client: Client,
 }
 
 impl From<&ChatClient> for BatchClient {
@@ -46,6 +48,7 @@ impl From<&ChatClient> for BatchClient {
             endpoint: "/v1/chat/completions".to_string(),
             model: client.model.clone(),
             files_client: FilesClient::from(client),
+            http_client: client.http_client.clone(),
         }
     }
 }
@@ -434,9 +437,9 @@ impl BatchClient {
         input_file_id: impl AsRef<str>,
         metadata: HashMap<String, String>,
     ) -> Result<Batch, CreateBatchError> {
-        let client = Client::new();
         let url = remove_trailing_slash(self.batches_url());
-        let response = client
+        let response = self
+            .http_client
             .post(url)
             .header("Authorization", format!("Bearer {}", self.api_key))
             .header("Content-Type", "application/json")
@@ -474,9 +477,9 @@ impl BatchClient {
 
     /// Get the status of a batch.
     pub async fn get_batch_status(&self, batch_id: &str) -> Result<Batch, GetBatchStatusError> {
-        let client = Client::new();
         let url = self.batches_url().join(batch_id).unwrap();
-        let response = client
+        let response = self
+            .http_client
             .get(url)
             .header("Authorization", format!("Bearer {}", self.api_key))
             .header("Content-Type", "application/json")
@@ -570,8 +573,8 @@ impl BatchClient {
 
     /// Cancel a batch.
     pub async fn cancel_batch(&self, batch_id: &str) -> Result<Batch, CancelBatchError> {
-        let client = Client::new();
-        let response = client
+        let response = self
+            .http_client
             .post(
                 self.batches_url()
                     .join(batch_id)
@@ -653,8 +656,8 @@ impl BatchClient {
             url.set_query(Some(&query_params.join("&")));
         }
 
-        let client = Client::new();
-        let response = client
+        let response = self
+            .http_client
             .get(remove_trailing_slash(url))
             .header("Authorization", format!("Bearer {}", self.api_key))
             .header("Content-Type", "application/json")

src/batch.rs

@@ -67,6 +67,9 @@ pub struct ChatClient {
 
     /// Semaphore to limit the maximum number of concurrent requests
     pub semaphore: Semaphore,
+
+    /// Shared HTTP client with connection pooling
+    pub http_client: Client,
 }
 
 /// The role of a message.
@@ -570,6 +573,7 @@ impl ChatClient {
             reasoning_effort: None,
             extra_body: None,
             semaphore: Semaphore::new(100),
+            http_client: crate::utils::pooled_client(),
         }
     }
 
@@ -1252,9 +1256,8 @@ impl ChatClient {
     async fn chat_uncached(&self, chat_request: &ChatRequest) -> Result<String, ChatError> {
         let _permit = self.semaphore.acquire().await.unwrap();
 
-        let reqwest_client = Client::new();
-
-        let response = reqwest_client
+        let response = self
+            .http_client
             .post(self.chat_completions_url())
             .header("Authorization", format!("Bearer {}", self.api_key.clone()))
             .header("Content-Type", "application/json")

src/chat_completions.rs

@@ -100,6 +100,9 @@ pub struct EmbeddingsClient {
 
     /// Semaphore to limit the maximum number of concurrent requests
     pub semaphore: Semaphore,
+
+    /// Shared HTTP client with connection pooling
+    pub http_client: Client,
 }
 
 /// Errors that can occur when interacting with the ChatGPT API.
@@ -164,6 +167,7 @@ impl EmbeddingsClient {
             backup_cache_directory: None,
             extra_body: None,
             semaphore: Semaphore::new(100),
+            http_client: crate::utils::pooled_client(),
         }
     }
 
@@ -478,9 +482,8 @@ impl EmbeddingsClient {
     ) -> Result<String, EmbeddingsError> {
         let _permit = self.semaphore.acquire().await.unwrap();
 
-        let client = Client::new();
-
-        let response = client
+        let response = self
+            .http_client
             .post(self.embeddings_url())
             .header("Authorization", format!("Bearer {}", self.api_key))
             .header("Content-Type", "application/json")

src/embeddings.rs

@@ -14,14 +14,15 @@ use crate::{
 };
 
 /// A client for interacting with the OpenAI Files API.
-#[derive(Debug)]
 pub struct FilesClient {
     /// The API key to use for the OpenAI API.
     pub api_key: String,
     /// The base URL of the OpenAI API.
     pub base_url: url::Url,
     /// The path to the Files API.
     pub files_path: String,
+    /// Shared HTTP client with connection pooling
+    pub http_client: Client,
 }
 
 impl From<&crate::chat_completions::ChatClient> for FilesClient {
@@ -30,6 +31,7 @@ impl From<&crate::chat_completions::ChatClient> for FilesClient {
             api_key: client.api_key.clone(),
             base_url: client.base_url.clone(),
             files_path: "files/".to_string(),
+            http_client: client.http_client.clone(),
         }
     }
 }
@@ -156,6 +158,7 @@ impl FilesClient {
             api_key: api_key.into(),
             base_url: url::Url::parse("https://api.openai.com/v1/").unwrap(),
             files_path: "files/".to_string(),
+            http_client: crate::utils::pooled_client(),
         }
     }
 
@@ -206,9 +209,9 @@ impl FilesClient {
             .text("purpose", format!("{:?}", purpose).to_lowercase())
             .part("file", file_part);
 
-        let client = Client::new();
         let url = remove_trailing_slash(self.files_url());
-        let response = client
+        let response = self
+            .http_client
             .post(url.clone())
             .header("Authorization", format!("Bearer {}", self.api_key))
             .multipart(form)
@@ -254,9 +257,9 @@ impl FilesClient {
             .text("purpose", format!("{:?}", purpose).to_lowercase())
             .part("file", file_part);
 
-        let client = Client::new();
         let url = remove_trailing_slash(self.files_url());
-        let response = client
+        let response = self
+            .http_client
             .post(url.clone())
             .header("Authorization", format!("Bearer {}", self.api_key))
             .multipart(form)
@@ -292,8 +295,8 @@ impl FilesClient {
     /// # });
     /// ```
     pub async fn list_files(&self) -> Result<FileList, FilesError> {
-        let client = Client::new();
-        let response = client
+        let response = self
+            .http_client
             .get(self.files_url())
             .header("Authorization", format!("Bearer {}", self.api_key))
             .send()
@@ -315,8 +318,8 @@ impl FilesClient {
     /// # });
     /// ```
     pub async fn retrieve_file(&self, file_id: &str) -> Result<FileObject, FilesError> {
-        let client = Client::new();
-        let response = client
+        let response = self
+            .http_client
             .get(self.files_url().join(file_id).unwrap())
             .header("Authorization", format!("Bearer {}", self.api_key))
             .send()
@@ -338,8 +341,8 @@ impl FilesClient {
     /// # });
     /// ```
     pub async fn delete_file(&self, file_id: &str) -> Result<DeletedFile, FilesError> {
-        let client = Client::new();
-        let response = client
+        let response = self
+            .http_client
             .delete(self.files_url().join(file_id).unwrap())
             .header("Authorization", format!("Bearer {}", self.api_key))
             .send()
@@ -361,12 +364,12 @@ impl FilesClient {
     /// # });
     /// ```
     pub async fn download_file(&self, file_id: &str) -> Result<String, FilesError> {
-        let client = Client::new();
         let url = self
             .files_url()
             .join(&format!("{file_id}/content"))
             .unwrap();
-        let response = client
+        let response = self
+            .http_client
             .get(url)
             .header("Authorization", format!("Bearer {}", self.api_key))
             .send()

src/files.rs

@@ -24,3 +24,12 @@ pub(crate) fn remove_trailing_slash(url: url::Url) -> url::Url {
     url.set_path(path);
     url
 }
+
+/// Create a shared reqwest::Client with connection pooling configured for high concurrency.
+pub(crate) fn pooled_client() -> reqwest::Client {
+    reqwest::Client::builder()
+        .pool_max_idle_per_host(256)
+        .pool_idle_timeout(std::time::Duration::from_secs(300))
+        .build()
+        .expect("Failed to build HTTP client")
+}