chore: Move all routes under routes directory (#2513)

closes #2504

server/routes/api/middlewares/pagination.js

@@ -0,0 +1,70 @@
+// @flow
+import querystring from "querystring";
+import { type Context } from "koa";
+import { InvalidRequestError } from "../../../errors";
+
+export default function pagination(options?: Object) {
+  return async function paginationMiddleware(
+    ctx: Context,
+    next: () => Promise<*>
+  ) {
+    const opts = {
+      defaultLimit: 15,
+      defaultOffset: 0,
+      maxLimit: 100,
+      ...options,
+    };
+
+    let query = ctx.request.query;
+    let body = ctx.request.body;
+
+    // $FlowFixMe
+    let limit = query.limit || body.limit;
+    // $FlowFixMe
+    let offset = query.offset || body.offset;
+
+    if (limit && isNaN(limit)) {
+      throw new InvalidRequestError(`Pagination limit must be a valid number`);
+    }
+    if (offset && isNaN(offset)) {
+      throw new InvalidRequestError(`Pagination offset must be a valid number`);
+    }
+
+    limit = parseInt(limit || opts.defaultLimit, 10);
+    offset = parseInt(offset || opts.defaultOffset, 10);
+
+    if (limit > opts.maxLimit) {
+      throw new InvalidRequestError(
+        `Pagination limit is too large (max ${opts.maxLimit})`
+      );
+    }
+    if (limit <= 0) {
+      throw new InvalidRequestError(`Pagination limit must be greater than 0`);
+    }
+    if (offset < 0) {
+      throw new InvalidRequestError(
+        `Pagination offset must be greater than or equal to 0`
+      );
+    }
+
+    /* $FlowFixMeNowPlease This comment suppresses an error found when upgrading
+     * flow-bin@0.104.0. To view the error, delete this comment and run Flow. */
+    ctx.state.pagination = {
+      limit,
+      offset,
+    };
+
+    // $FlowFixMe
+    query.limit = ctx.state.pagination.limit;
+    // $FlowFixMe
+    query.offset = ctx.state.pagination.offset + query.limit;
+
+    /* $FlowFixMeNowPlease This comment suppresses an error found when upgrading
+     * flow-bin@0.104.0. To view the error, delete this comment and run Flow. */
+    ctx.state.pagination.nextPath = `/api${
+      ctx.request.path
+    }?${querystring.stringify(query)}`;
+
+    return next();
+  };
+}