From 49632ea19f6dc24e0174c2dfa47ffc253261db3d Mon Sep 17 00:00:00 2001
From: Louise Davies <louise.davies@stfc.ac.uk>
Date: Wed, 29 Mar 2023 16:49:57 +0100
Subject: [PATCH] fix!: add url_prefix param to fix swagger docs at non-root
 paths #408

---
 datagateway_api/config.yaml.example    | 1 +
 datagateway_api/src/api_start_utils.py | 8 ++++----
 datagateway_api/src/common/config.py   | 5 +++++
 datagateway_api/src/main.py            | 7 +++++++
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/datagateway_api/config.yaml.example b/datagateway_api/config.yaml.example
index 5224f796..0634e1ac 100644
--- a/datagateway_api/config.yaml.example
+++ b/datagateway_api/config.yaml.example
@@ -30,3 +30,4 @@ host: "127.0.0.1"
 port: "5000"
 test_user_credentials: { username: "root", password: "pw" }
 test_mechanism: "simple"
+url_prefix: "/"
diff --git a/datagateway_api/src/api_start_utils.py b/datagateway_api/src/api_start_utils.py
index ced74576..eb5d13b7 100644
--- a/datagateway_api/src/api_start_utils.py
+++ b/datagateway_api/src/api_start_utils.py
@@ -69,8 +69,8 @@ def handle_error(self, e):
 
 def configure_datagateway_api_swaggerui_blueprint(flask_app):
     swaggerui_blueprint = get_swaggerui_blueprint(
-        base_url=Config.config.datagateway_api.extension,
-        api_url="/datagateway-api/openapi.json",
+        base_url=f"{Config.config.url_prefix}{Config.config.datagateway_api.extension}",
+        api_url=f"{Config.config.url_prefix}/datagateway-api/openapi.json",
         config={"app_name": "DataGateway API OpenAPI Spec"},
         blueprint_name="DataGateway API Swagger UI",
     )
@@ -83,8 +83,8 @@ def configure_datagateway_api_swaggerui_blueprint(flask_app):
 
 def configure_search_api_swaggerui_blueprint(flask_app):
     swaggerui_blueprint = get_swaggerui_blueprint(
-        base_url=Config.config.search_api.extension,
-        api_url="/search-api/openapi.json",
+        base_url=f"{Config.config.url_prefix}{Config.config.search_api.extension}",
+        api_url=f"{Config.config.url_prefix}/search-api/openapi.json",
         config={"app_name": "Search API OpenAPI Spec"},
         blueprint_name="Search API Swagger UI",
     )
diff --git a/datagateway_api/src/common/config.py b/datagateway_api/src/common/config.py
index 9f190bb7..204e96f1 100644
--- a/datagateway_api/src/common/config.py
+++ b/datagateway_api/src/common/config.py
@@ -32,6 +32,8 @@ def validate_extension(extension):
             raise ValueError("must start with '/'")
         if extension.endswith("/") and len(extension) != 1:
             raise ValueError("must not end with '/'")
+        if extension == "/":
+            extension = ""
 
     return extension
 
@@ -183,6 +185,9 @@ class APIConfig(BaseModel):
     search_api: Optional[SearchAPI]
     test_mechanism: Optional[StrictStr]
     test_user_credentials: Optional[TestUserCredentials]
+    url_prefix: StrictStr
+
+    _validate_extension = validator("url_prefix", allow_reuse=True)(validate_extension)
 
     @classmethod
     def load(cls, path=Path(__file__).parent.parent.parent / "config.yaml"):
diff --git a/datagateway_api/src/main.py b/datagateway_api/src/main.py
index fd2c04dd..3bb1d1b0 100644
--- a/datagateway_api/src/main.py
+++ b/datagateway_api/src/main.py
@@ -9,6 +9,8 @@
 )
 from datagateway_api.src.common.config import Config
 from datagateway_api.src.common.logger_setup import setup_logger
+from werkzeug.middleware.dispatcher import DispatcherMiddleware
+from werkzeug.wrappers import Response
 
 setup_logger()
 log = logging.getLogger()
@@ -18,8 +20,13 @@
 api, specs = create_app_infrastructure(app)
 create_api_endpoints(app, api, specs)
 create_openapi_endpoints(app, specs)
+app.config["APPLICATION_ROOT"] = Config.config.url_prefix
 
 if __name__ == "__main__":
+    app.wsgi_app = DispatcherMiddleware(
+        Response('Not Found', status=404),
+        {Config.config.url_prefix: app.wsgi_app}
+    )
     app.run(
         host=Config.config.host,
         port=Config.config.port,