html_url,issue_url,id,node_id,user,user_label,created_at,updated_at,author_association,body,reactions,issue,issue_label,performed_via_github_app
https://github.com/simonw/datasette/issues/1439#issuecomment-1059854864,https://api.github.com/repos/simonw/datasette/issues/1439,1059854864,IC_kwDOBm6k_c4_LBoQ,9599,simonw,2022-03-05T23:59:05Z,2022-03-05T23:59:05Z,OWNER,"OK, for that percentage thing: the Python core implementation of URL percentage escaping deliberately ignores two of the characters we want to escape: `.` and `-`:

https://github.com/python/cpython/blob/6927632492cbad86a250aa006c1847e03b03e70b/Lib/urllib/parse.py#L780-L783

```python
_ALWAYS_SAFE = frozenset(b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
                         b'abcdefghijklmnopqrstuvwxyz'
                         b'0123456789'
                         b'_.-~')
```
It also defaults to skipping `/` (passed as a `safe=` parameter to various things).

I'm going to try borrowing and modifying the core of the Python implementation: https://github.com/python/cpython/blob/6927632492cbad86a250aa006c1847e03b03e70b/Lib/urllib/parse.py#L795-L814
```python
class _Quoter(dict):
    """"""A mapping from bytes numbers (in range(0,256)) to strings.
    String values are percent-encoded byte values, unless the key < 128, and
    in either of the specified safe set, or the always safe set.
    """"""
    # Keeps a cache internally, via __missing__, for efficiency (lookups
    # of cached keys don't call Python code at all).
    def __init__(self, safe):
        """"""safe: bytes object.""""""
        self.safe = _ALWAYS_SAFE.union(safe)

    def __repr__(self):
        return f""<Quoter {dict(self)!r}>""

    def __missing__(self, b):
        # Handle a cache miss. Store quoted string in cache and return.
        res = chr(b) if b in self.safe else '%{:02X}'.format(b)
        self[b] = res
        return res
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",973139047,Rethink how .ext formats (v.s. ?_format=) works before 1.0,
https://github.com/simonw/datasette/issues/1439#issuecomment-1059853526,https://api.github.com/repos/simonw/datasette/issues/1439,1059853526,IC_kwDOBm6k_c4_LBTW,9599,simonw,2022-03-05T23:49:59Z,2022-03-05T23:49:59Z,OWNER,"I want to try regular percentage encoding, except that it also encodes both the `-` and the `.` characters, AND it uses `-` instead of `%` as the encoding character.

Should check what it does with emoji too.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",973139047,Rethink how .ext formats (v.s. ?_format=) works before 1.0,
https://github.com/simonw/datasette/issues/1439#issuecomment-1059851259,https://api.github.com/repos/simonw/datasette/issues/1439,1059851259,IC_kwDOBm6k_c4_LAv7,9599,simonw,2022-03-05T23:35:47Z,2022-03-05T23:35:59Z,OWNER,"This [comment from glyph](https://twitter.com/glyph/status/1500244937312329730) got me thinking:

> Have you considered replacing % with some other character and then using percent-encoding?

What happens if a table name includes a `%` character and that ends up getting mangled by a misbehaving proxy?

I should consider `%` in the escaping system too. And maybe go with that suggestion of using percent-encoding directly but with a different character.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",973139047,Rethink how .ext formats (v.s. ?_format=) works before 1.0,
https://github.com/simonw/datasette/issues/1439#issuecomment-1059850369,https://api.github.com/repos/simonw/datasette/issues/1439,1059850369,IC_kwDOBm6k_c4_LAiB,9599,simonw,2022-03-05T23:28:56Z,2022-03-05T23:28:56Z,OWNER,"Lots of great conversations about the dash encoding implementation on Twitter: https://twitter.com/simonw/status/1500228316309061633

@dracos helped me figure out a simpler regex: https://twitter.com/dracos/status/1500236433809973248

`^/(?P<database>[^/]+)/(?P<table>[^\/\-\.]*|\-/|\-\.|\-\-)*(?P<format>\.\w+)?$`

![image](https://user-images.githubusercontent.com/9599/156903088-c01933ae-4713-4e91-8d71-affebf70b945.png)
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",973139047,Rethink how .ext formats (v.s. ?_format=) works before 1.0,
https://github.com/simonw/datasette/issues/1439#issuecomment-1059836599,https://api.github.com/repos/simonw/datasette/issues/1439,1059836599,IC_kwDOBm6k_c4_K9K3,9599,simonw,2022-03-05T21:52:10Z,2022-03-05T21:52:10Z,OWNER,Blogged about this here: https://simonwillison.net/2022/Mar/5/dash-encoding/,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",973139047,Rethink how .ext formats (v.s. ?_format=) works before 1.0,
https://github.com/simonw/datasette/issues/1439#issuecomment-1059822391,https://api.github.com/repos/simonw/datasette/issues/1439,1059822391,IC_kwDOBm6k_c4_K5s3,9599,simonw,2022-03-05T19:50:12Z,2022-03-05T19:50:12Z,OWNER,I'm going to move this work to a PR.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",973139047,Rethink how .ext formats (v.s. ?_format=) works before 1.0,
https://github.com/simonw/datasette/issues/1439#issuecomment-1059822151,https://api.github.com/repos/simonw/datasette/issues/1439,1059822151,IC_kwDOBm6k_c4_K5pH,9599,simonw,2022-03-05T19:48:35Z,2022-03-05T19:48:35Z,OWNER,Those new docs: https://github.com/simonw/datasette/blob/d1cb73180b4b5a07538380db76298618a5fc46b6/docs/internals.rst#dash-encoding,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",973139047,Rethink how .ext formats (v.s. ?_format=) works before 1.0,
https://github.com/simonw/datasette/issues/1439#issuecomment-1059802318,https://api.github.com/repos/simonw/datasette/issues/1439,1059802318,IC_kwDOBm6k_c4_K0zO,9599,simonw,2022-03-05T17:34:33Z,2022-03-05T17:34:33Z,OWNER,"Wrote documentation:

<img width=""741"" alt=""Dash encoding. Datasette uses a custom encoding scheme in some places, called dash encoding. This is primarily used for table names and row primary keys, to avoid any confusion between / characters in those values and the Datasette URL that references them. Dash encoding applies the following rules, in order: 1.    All single - characters are replaced by -- 2. . characters are replaced by -. 3. / characters are replaced by ./ These rules are applied in reverse order to decode a dash encoded string."" src=""https://user-images.githubusercontent.com/9599/156893903-5723f60e-e054-4365-84bc-f3084d11183d.png"">

","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",973139047,Rethink how .ext formats (v.s. ?_format=) works before 1.0,