v4.1.1

Author: lpil

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## v4.1.1 - 2025-07-22
+
+- Fixed a bug where `set_cookie` would fail to overwrite an existing cookie.
+
 ## v4.1.0 - 2025-07-06
 
 - Updated for latest `gleam_stdlib`.

gleam.toml

@@ -1,5 +1,5 @@
 name = "gleam_http"
-version = "4.1.0"
+version = "4.1.1"
 licences = ["Apache-2.0"]
 description = "Types and functions for Gleam HTTP clients and servers"
 gleam = ">= 1.0.0"

src/gleam/http/request.gleam

@@ -243,22 +243,29 @@ pub fn set_path(req: Request(body), path: String) -> Request(body) {
   Request(..req, path: path)
 }
 
-/// Send a cookie with a request
+/// Set a cookie on a request, replacing any previous cookie with that name.
+///
+/// All cookies stored in a single header named `cookie`. There should be
+/// at most one header with the name `cookie`, otherwise this function cannot
+/// guarentee that previous cookies with the same name are replaced.
 ///
-/// Multiple cookies are added to the same cookie header.
 pub fn set_cookie(req: Request(body), name: String, value: String) {
-  let new_cookie_string = string.join([name, value], "=")
+  // Get the cookies
+  let #(cookies, headers) =
+    list.key_pop(req.headers, "cookie") |> result.unwrap(#("", req.headers))
 
-  let #(cookies_string, headers) = case list.key_pop(req.headers, "cookie") {
-    Ok(#(cookies_string, headers)) -> {
-      let cookies_string =
-        string.join([cookies_string, new_cookie_string], "; ")
-      #(cookies_string, headers)
-    }
-    Error(Nil) -> #(new_cookie_string, req.headers)
-  }
+  // Parse them
+  let cookies =
+    string.split(cookies, ";")
+    |> list.filter_map(fn(c) { string.trim_start(c) |> string.split_once("=") })
+
+  // Set the new cookie, replacing any previous one with the same name
+  let cookies =
+    list.key_set(cookies, name, value)
+    |> list.map(fn(pair) { pair.0 <> "=" <> pair.1 })
+    |> string.join("; ")
 
-  Request(..req, headers: [#("cookie", cookies_string), ..headers])
+  Request(..req, headers: [#("cookie", cookies), ..headers])
 }
 
 /// Fetch the cookies sent in a request.

test/gleam/http/request_test.gleam

@@ -451,6 +451,21 @@ pub fn set_req_cookies_test() {
   |> should.equal(Ok("k1=v1; k2=v2"))
 }
 
+pub fn set_req_cookies_overwrite_test() {
+  let request =
+    request.new()
+    |> request.set_cookie("k1", "k1")
+    |> request.set_cookie("k2", "k2")
+    |> request.set_cookie("k3", "k3")
+    |> request.set_cookie("k4", "k4")
+    |> request.set_cookie("k2", "k2-updated")
+    |> request.set_cookie("k4", "k4-updated")
+
+  request
+  |> request.get_header("cookie")
+  |> should.equal(Ok("k1=k1; k2=k2-updated; k3=k3; k4=k4-updated"))
+}
+
 pub fn remove_cookie_from_request_test() {
   let req =
     request.new()