Adds "remove cookie" function to request module

src/gleam/http/request.gleam

@@ -1,5 +1,6 @@
 import gleam/http.{type Header, type Method, type Scheme, Get}
 import gleam/http/cookie
+import gleam/io
 import gleam/list
 import gleam/option.{type Option}
 import gleam/result
@@ -284,3 +285,28 @@ pub fn get_cookies(req) -> List(#(String, String)) {
   })
   |> list.flatten()
 }
+
+/// Remove a cookie from a request
+///
+/// Remove a cookie from the request. If no cookie is found return the request unchanged.
+/// This will not remove the cookie from the client.
+pub fn remove_cookie(req: Request(body), name: String) {
+  case list.key_pop(req.headers, "cookie") {
+    Ok(#(cookies_string, headers)) -> {
+      let new_cookies_string =
+        string.split(cookies_string, ";")
+        |> list.filter(fn(str) {
+          string.trim(str)
+          |> string.split_once("=")
+          // Keep cookie if name does not match
+          |> result.map(fn(tup) { tup.0 != name })
+          // Don't do anything with malformed cookies
+          |> result.unwrap(True)
+        })
+        |> string.join(";")
+
+      Request(..req, headers: [#("cookie", new_cookies_string), ..headers])
+    }
+    Error(_) -> req
+  }
+}

test/gleam/http/request_test.gleam

@@ -450,3 +450,40 @@ pub fn set_req_cookies_test() {
   |> request.get_header("cookie")
   |> should.equal(Ok("k1=v1; k2=v2"))
 }
+
+pub fn remove_cookie_from_request_test() {
+  let req =
+    request.new()
+    |> request.set_cookie("FIRST_COOKIE", "first")
+    |> request.set_cookie("SECOND_COOKIE", "second")
+    |> request.set_cookie("THIRD_COOKIE", "third")
+
+  req
+  |> request.get_header("cookie")
+  |> should.be_ok
+  |> should.equal(
+    "FIRST_COOKIE=first; SECOND_COOKIE=second; THIRD_COOKIE=third",
+  )
+
+  let modified_req =
+    req
+    |> request.remove_cookie("SECOND_COOKIE")
+
+  modified_req
+  |> request.get_header("cookie")
+  |> should.be_ok
+  |> should.equal("FIRST_COOKIE=first; THIRD_COOKIE=third")
+}
+
+pub fn only_remove_matching_cookies_test() {
+  request.new()
+  |> request.set_cookie("FIRST_COOKIE", "first")
+  |> request.set_cookie("SECOND_COOKIE", "second")
+  |> request.set_cookie("THIRD_COOKIE", "third")
+  |> request.remove_cookie("SECOND")
+  |> request.get_header("cookie")
+  |> should.be_ok
+  |> should.equal(
+    "FIRST_COOKIE=first; SECOND_COOKIE=second; THIRD_COOKIE=third",
+  )
+}