feat(导出): 添加Markdown导出功能并支持_format参数

添加Markdown格式导出功能，包括导出链接和选项表单
同时修改多处视图以支持通过_format参数指定导出格式

datasette/templates/table.html

@@ -124,7 +124,7 @@
     <p><a class="not-underlined" title="{{ query.sql }}" href="{{ urls.database(database) }}?{{ {'sql': query.sql}|urlencode|safe }}{% if query.params %}&amp;{{ query.params|urlencode|safe }}{% endif %}">&#x270e; <span class="underlined">View and edit SQL</span></a></p>
 {% endif %}
 
-<p class="export-links">This data as {% for name, url in renderers.items() %}<a href="{{ url }}">{{ name }}</a>{{ ", " if not loop.last }}{% endfor %}{% if display_rows %}, <a href="{{ url_csv }}">CSV</a> (<a href="#export">advanced</a>){% endif %}</p>
+<p class="export-links">This data as {% for name, url in renderers.items() %}<a href="{{ url }}">{{ name }}</a>{{ ", " if not loop.last }}{% endfor %}{% if display_rows %}, <a href="{{ url_csv }}">CSV</a> (<a href="#export">advanced</a>), <a href="{{ url_markdown }}">Markdown</a> (<a href="#export-markdown">advanced</a>){% endif %}</p>
 
 {% if suggested_facets %}
     {% include "_suggested_facets.html" %}
@@ -186,6 +186,20 @@ window._setColumnTypeData = {{ set_column_type_ui|tojson }};
                 {% endfor %}
             </p>
         </form>
+        <div id="export-markdown" class="advanced-export">
+            <form class="core" action="{{ url_markdown_path }}" method="get">
+                <p>
+                    Markdown options:
+                    {% if expandable_columns %}<label><input type="checkbox" name="_labels" checked> expand labels</label>{% endif %}
+                    {% if next_url and settings.allow_csv_stream %}<label><input type="checkbox" name="_stream"> export all rows (unlimited)</label>{% endif %}
+                    <label>Max rows: <input type="number" name="_max_rows" value="500" min="0" max="10000" style="width: 80px;"></label>
+                    <input type="submit" value="Export Markdown">
+                    {% for key, value in url_markdown_hidden_args %}
+                        <input type="hidden" name="{{ key }}" value="{{ value }}">
+                    {% endfor %}
+                </p>
+            </form>
+        </div>
     </div>
 {% endif %}
 

datasette/views/base.py

@@ -206,16 +206,21 @@ class DataView(BaseView):
     async def as_csv(self, request, database):
         return await stream_csv(self.ds, self.data, request, database)
 
+    async def as_markdown(self, request, database):
+        return await stream_markdown(self.ds, self.data, request, database)
+
     async def get(self, request):
         db = await self.ds.resolve_database(request)
         database = db.name
         database_route = db.route
 
-        _format = request.url_vars["format"]
+        _format = request.url_vars["format"] or request.args.get("_format")
         data_kwargs = {}
 
         if _format == "csv":
             return await self.as_csv(request, database_route)
+        elif _format == "markdown":
+            return await self.as_markdown(request, database_route)
 
         if _format is None:
             # HTML views default to expanding all foreign key labels

datasette/views/database.py

@@ -40,7 +40,7 @@ from . import Context
 
 class DatabaseView(View):
     async def get(self, request, datasette):
-        format_ = request.url_vars.get("format") or "html"
+        format_ = request.url_vars.get("format") or request.args.get("_format") or "html"
 
         await datasette.refresh_schemas()
 
@@ -591,7 +591,7 @@ class QueryView(View):
         if params.get("_timelimit"):
             extra_args["custom_time_limit"] = int(params["_timelimit"])
 
-        format_ = request.url_vars.get("format") or "html"
+        format_ = request.url_vars.get("format") or request.args.get("_format") or "html"
 
         query_error = None
         results = None

datasette/views/table.py

@@ -976,7 +976,7 @@ async def table_view_traced(datasette, request):
     if request.method == "POST":
         return Response.text("Method not allowed", status=405)
 
-    format_ = request.url_vars.get("format") or "html"
+    format_ = request.url_vars.get("format") or request.args.get("_format") or "html"
     extra_extras = None
     context_for_html_hack = False
     default_labels = False
@@ -2072,6 +2072,12 @@ async def table_view_data(
             path_with_format(request=request, format="csv", extra_qs=url_csv_args)
         )
         url_csv_path = url_csv.split("?")[0]
+        # Markdown export URL
+        url_markdown_args = {**url_labels_extra}
+        url_markdown = datasette.urls.path(
+            path_with_format(request=request, format="markdown", extra_qs=url_markdown_args)
+        )
+        url_markdown_path = url_markdown.split("?")[0]
         data.update(
             {
                 "url_csv": url_csv,
@@ -2082,6 +2088,13 @@ async def table_view_data(
                     if key not in ("_labels", "_facet", "_size")
                 ]
                 + [("_size", "max")],
+                "url_markdown": url_markdown,
+                "url_markdown_path": url_markdown_path,
+                "url_markdown_hidden_args": [
+                    (key, value)
+                    for key, value in urllib.parse.parse_qsl(request.query_string)
+                    if key not in ("_labels", "_facet", "_size", "_max_rows")
+                ],
             }
         )
         # if no sort specified AND table has a single primary key,