add rfc for renaming types and fields

rfcs/renaming-types-and-fields.md

@@ -0,0 +1,108 @@
+## Rename type and field names for Postgres and Remote Schemas
+
+When adding a table or a remote schema (or after adding), users can be given a choice to rename
+types and fields so that they are graphql-conformant, avoid conflicts, or simply more usable.
+
+### For postgres:
+
+For postgres, we already have a `set_table_custom_fields` API which allows you to rename top-level fields and column names: https://hasura.io/docs/1.0/graphql/manual/api-reference/schema-metadata-api/table-view.html#set-table-custom-fields
+
+This can include `custom_table_type` key which will change the name of the type of table. E.g.
+
+```
+{
+   "type": "set_table_custom_fields",
+   "version": 2,
+   "args": {
+     "table": "author",
+     "custom_root_fields": {
+        "select": "Authors",
+        "select_by_pk": "Author",
+        "select_aggregate": "AuthorAggregate",
+     },
+     "custom_column_names": {
+        "id": "authorId"
+     },
+     “custom_table_type”: “myauthor”
+   }
+}
+```
+
+### For remote schemas:
+
+There are 2 independent things that are required:
+
+1. Namespacing
+2. Customise type and field names (also enables prefixing)
+
+#### Namespacing
+
+`add_remote_schema` can take a `namespace` key. If this key is set, then the fields of the remote schema are added under the namespace respectively i.e. an object field with name `namespace`  is added inside `query_root`, `mutation_root` and `subscription_root` and the remote schema fields are added inside this object field.
+
+E.g. suppose user provides namespace “userservice” when adding remote schema.
+
+```
+{
+    "type": "add_remote_schema",
+    "args": {
+        "name": "my remote schema",
+        "definition": {
+            "url": "https://remote-server.com/graphql",
+            "forward_client_headers": false,
+            "namespace": “userservice”
+        }
+    }
+}
+```
+
+Then you can query as:
+
+```
+query {
+  userservice {
+    getUser
+}
+
+mutation {
+  userservice {
+    deleteUser
+}
+```
+
+#### Customise type and field names 
+
+When adding a remote schema, a custom spec for renaming types and fields can be given.
+
+```
+{
+    "type": "add_remote_schema",
+    "args": {
+        "name": "my remote schema",
+        "definition": {
+            "url": "https://remote-server.com/graphql",
+            "forward_client_headers": false,
+        },
+        "custom_types": [
+          {
+            "type": "Query",
+            "custom_fields": [
+              {
+                "field": "getUser",
+                "new_field": "getRemoteUser"
+              },
+              {
+                "field": "getUser2",
+                "new_field": "getRemoteUser2"
+              }
+            ]
+          },
+          {
+            "type": "User",
+            "new_type": "RemoteUser"
+          }
+        ]
+    }
+}
+```
+
+The main parameters here are `new_type` and `new_field`.