id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,pull_request,body,repo,type,active_lock_reason,performed_via_github_app,reactions,draft,state_reason
1099723916,I_kwDOBm6k_c5BjHSM,1590,Table+query JSON and CSV links broken when using `base_url` setting,1001306,closed,0,,7571612,11,2022-01-11T23:46:39Z,2022-01-14T01:16:34Z,2022-01-14T01:16:08Z,NONE,,"Datasette appends the prefix found in the `base_url` setting twice if a `base_url` is set.

In the follow asgi example, I'm hosting a custom Datasette instance:

```python
# asgi.py
import pathlib
from asgi_cors import asgi_cors
from channels.routing import URLRouter
from django.urls import re_path
from datasette.app import Datasette

datasette_ = Datasette(
    files=[],
    settings={
        ""base_url"": ""/datasettes/"",
        ""plugins"": {}
    },
    config_dir=pathlib.Path('.'),
)
application = URLRouter([
  re_path(r""^datasettes/.*"", asgi_cors(datasette_.app(), allow_all=True)),
])
```

Running it with:
```shell
$ daphne -p 8002 asgi:application
```

Using a simple query on the `_memory` table: 
```sql
select sqlite_version()
```

http://localhost:8002/datasettes/_memory?sql=select+sqlite_version%28%29

It renders the following upon inspection:
![image](https://user-images.githubusercontent.com/1001306/149038851-aa842950-126a-467c-9a86-fae13bce6221.png)

I am using datasette version `0.59.4`",107914493,issue,,,"{""url"": ""https://api.github.com/repos/simonw/datasette/issues/1590/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed