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modules/client/rooms/messages: Implement pagination tokens.

This commit is contained in:
Jason Volk 2018-02-23 22:08:09 -08:00
parent ff2903900b
commit 9d1d0c84a9

View file

@ -12,29 +12,24 @@
using namespace ircd;
struct pagination_tokens
{
uint8_t limit;
char dir;
m::event::id::buf from;
m::event::id::buf to;
pagination_tokens(const resource::request &);
};
resource::response
get__messages(client &client,
const resource::request &request,
const m::room::id &room_id)
{
const string_view &from
const pagination_tokens page
{
request.query.at("from")
};
const string_view &to
{
request.query["to"]
};
const char &dir
{
request.query.at("dir").at(0)
};
const uint16_t limit
{
request.query["limit"]? lex_cast<uint16_t>(request.query.at("limit")) : ushort(10)
request
};
const string_view &filter
@ -47,24 +42,45 @@ get__messages(client &client,
room_id
};
m::event::id::buf start, end;
std::vector<json::value> ret;
ret.reserve(limit);
ret.reserve(page.limit);
m::room::messages it{room};
for(; it && ret.size() < limit; dir == 'b'? --it : ++it)
ret.emplace_back(*it);
const string_view start
m::room::messages it
{
dir == 'b'? from : ":1234"
room, page.from
};
const string_view end
{
dir == 'b'? ":4321" : string_view{}
};
// Spec sez the 'from' token is exclusive
if(it && page.dir == 'b')
--it;
else if(it)
++it;
json::value chunk
for(; it; page.dir == 'b'? --it : ++it)
{
const m::event &event{*it};
if(page.to && at<"event_id"_>(event) == page.to)
{
if(page.dir != 'b')
start = at<"event_id"_>(event);
break;
}
ret.emplace_back(event);
if(ret.size() >= page.limit)
{
if(page.dir == 'b')
end = at<"event_id"_>(event);
else
start = at<"event_id"_>(event);
break;
}
}
const json::value chunk
{
ret.data(), ret.size()
};
@ -79,3 +95,55 @@ get__messages(client &client,
}
};
}
// Client-Server 6.3.6 query parameters
pagination_tokens::pagination_tokens(const resource::request &request)
try
:limit
{
// The maximum number of events to return. Default: 10.
// > we limit this to 255 via narrowing cast
request.query["limit"]?
uint8_t(lex_cast<ushort>(request.query.at("limit"))):
uint8_t(10)
}
,dir
{
// Required. The direction to return events from. One of: ["b", "f"]
request.query.at("dir").at(0)
}
,from
{
// Required. The token to start returning events from. This token can be
// obtained from a prev_batch token returned for each room by the sync
// API, or from a start or end token returned by a previous request to
// this endpoint.
url::decode(request.query.at("from"), from)
}
{
// The token to stop returning events at. This token can be obtained from
// a prev_batch token returned for each room by the sync endpoint, or from
// a start or end token returned by a previous request to this endpoint.
if(!empty(request.query["to"]))
url::decode(request.query.at("to"), to);
if(dir != 'b' && dir != 'f')
throw m::BAD_PAGINATION
{
"query parameter 'dir' must be 'b' or 'f'"
};
}
catch(const bad_lex_cast &)
{
throw m::BAD_PAGINATION
{
"query parameter 'limit' is invalid"
};
}
catch(const m::INVALID_MXID &)
{
throw m::BAD_PAGINATION
{
"query parameter 'from' or 'to' is not a valid token"
};
}