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Post an unencrypted message
One script reply has been approved by the moderators Verified

Post a plain text message to a Matrix chat room. The event type is "m.room.message" and the message type is "m.text".

Created by jaller94 849 days ago Viewed 13120 times
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Submitted by jaller94 Deno
Verified 849 days ago
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type Matrix = {
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  baseUrl: string;
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  token: string;
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};
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export async function main(matrix_res: Matrix, room: string, body: string) {
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  if (!matrix_res.token) {
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    throw Error("Sending a message requires an access token.");
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  }
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  const roomId = await resolveRoomAlias(matrix_res, room);
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  const txnId = `${Math.random()}`;
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  const resp = await fetch(
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    `${matrix_res.baseUrl}/_matrix/client/v3/rooms/${encodeURIComponent(
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      roomId,
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    )}/send/m.room.message/${txnId}`,
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    {
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      method: "PUT",
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      headers: {
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        Accept: "application/json",
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        Authorization: `Bearer ${matrix_res.token}`,
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        "Content-Type": "application/json",
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      },
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      body: JSON.stringify({
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        body,
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        msgtype: "m.text",
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      }),
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    },
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  );
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  if (!resp.ok) {
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    throw Error(`Failed to send message: Error HTTP${resp.status}`);
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  }
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  const eventId = (await resp.json())["event_id"];
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  if (typeof eventId !== "string") {
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    throw Error(
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      `Faulty Matrix server implementation: Server didn't provide event_id for this message.`,
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    );
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  }
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  return eventId;
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}
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/**
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 * Resolves a room alias to a room id.
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 * This is basically like resolving a domain name to an IP address.
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 */
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async function resolveRoomAlias(
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  matrix_res: Matrix,
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  room: string,
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): Promise<string> {
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  // Is it already a room ID?
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  if (room.startsWith("!")) {
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    return room;
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  }
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  const resp = await fetch(
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    `${
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      matrix_res.baseUrl
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    }/_matrix/client/v3/directory/room/${encodeURIComponent(room)}`,
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    {
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      headers: {
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        Accept: "application/json",
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        ...(matrix_res.token && {
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          Authorization: `Bearer ${matrix_res.token}`,
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        }),
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      },
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    },
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  );
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  if (!resp.ok) {
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    throw Error(`Failed to resolve room alias: Error HTTP${resp.status}`);
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  }
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  const roomId = (await resp.json())["room_id"];
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  if (typeof roomId !== "string") {
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    throw Error(
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      `Faulty Matrix server implementation: Server didn't provide room_id for this alias.`,
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    );
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  }
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  return roomId;
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}
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