API for checking if a username is already taken

CodeChallenge/api/users.py

@@ -209,3 +209,11 @@ def reset_password():
         return json_error("password reset failed")
 
     return jsonify(status="success", reason="password reset successfully")
+
+
+@bp.route("/<string:username>/exists", methods=["GET"])
+def username_exists(username):
+    exists = Users.query.filter_by(username=username).first() is not None
+    return jsonify(status="success",
+                   exists=exists,
+                   username=username)

tests/test_auth.py

@@ -97,3 +97,16 @@ def test_forgot_password(client, app):
         ))
 
         assert retval.status_code == 200
+
+
+def test_user_exists(client):
+
+    rv = client.get("/api/v1/users/cwhqsam/exists")
+    assert rv.status_code == 200
+    assert rv.json["exists"] is True
+    assert rv.json["username"] == "cwhqsam"
+
+    rv2 = client.get("/api/v1/users/foobar/exists")
+    assert rv2.status_code == 200
+    assert rv2.json["username"] == "foobar"
+    assert rv2.json["exists"] is False