Node.js API Pagination Support

Ray Cooke

Hi,

I'm trying to query the OpsGenie API from a Node.js app and I'm using the supplied Node.js library to do it. The library doesn't appear to have any support for paginated results and it appears the only way to do it from the API is using the paging section of the response which lists the next URL, however this is a long way down the call stack inside the library. Is there a recommended pattern for implementing pagination using the library or do I need to rewrite the library from scratch?

Cheers,

Ray

Ray Cooke

Transferred from thread above:

For those that find this and want an answer, please use the below (tested and works). It's substantially different, and more generic, to what I put earlier in this thread and more importantly works, whereas the earlier content I put won't because of the async nature of the API call.

/**
 * Query the OG API for data
 * 
 * @param {*} ogAPICall The API to call, e.g. opsgenie.incident.list
 * @param {*} queryJSON The query parameters, e.g. {query: "", sort: "insertedAt", order: "desc"}
 * @param {*[]} [results=[]] Internally used. Maintains a recursively constructed array of results
 * @param {*} [startAt=0] Interally used. The offset index for paged results fetching 
 * @returns {Promise<[]>} of results
 */
async function queryAPI(ogAPICall, queryJSON, results = [], startAt = 0) {

  // Set pagination parameters
  queryJSON.offset = startAt;
  queryJSON.limit = 100;
  queryJSON.direction = "next";

  return opsGeniePagedRequest(ogAPICall, queryJSON).then(response => {
    console.log(response);

    results = results.concat(response.data);

    // If there are more results to get then get them.
    /* 
     Note: In the situation where the number of results is a whole multiple of the limit
     one wasted API call will be made. This cannot be avoided without knowing the full
     number of results, which the API response doesn't currently provide.
     */
    if (response.data.length == queryJSON.limit) {
      // Chain up another promise
      return queryAPI(results, startAt + queryJSON.limit);
    }
    return results;

  }).catch(error => {
    console.error(error);
    return results;
  })
}

/**
 * Wrap an OpsGenie library API call in a Promise so that we can handle pagination
 * 
 * @param {*} ogAPICall The Ops Genie library API call to make
 * @param {*} queryJSON The JSON object defining the query parameters
 * @returns {Promise} that the API call will be made
 */
async function opsGeniePagedRequest(ogAPICall, queryJSON) {
  return new Promise((resolve, reject) => {
    ogAPICall(queryJSON, (error, response) => {
      if (error) reject(error);
      resolve(response);
    });
  });
}

An example of using the above would be:

let incidents = await queryAPI(opsgenie.incident.list, {query: "status : open", sort: "insertedAt", order: "desc"});