Changes Support

README.md

@@ -124,6 +124,64 @@ couch.mango(dbName, mangoQuery, parameters).then(({data, headers, status}) => {
 });
 ```
 
+## Trigger A Design Update
+```javascript
+const update = {
+ firstname: 'Rita',
+ middlename: '__delete__'
+};
+
+couch.design_update('database', 'someDocId', 'default', 'partialUpdate', update).then(({data, headers, status}) => {
+ // data is json response
+ // headers is an object with all response headers
+ // status is statusCode number
+}, err => {
+ // either request error occured
+ // ...or err.code=EDOCMISSING if document is missing
+ // ...or err.code=EUNKNOWN if statusCode is unexpected
+});
+```
+
+## Subscribe To Changes
+```javascript
+const dbName = "database";
+const mangoQuery = {
+ selector: {
+ $gte: {firstname: 'Ann'},
+ $lt: {firstname: 'George'} 
+ }
+};
+
+// This method will first be called with a null change and valid context, before any changes are posted.
+// The context has an unsubscribe() method that will release resources and disconnect.
+function changeCallback (change, context) {
+ if (!change) {
+ // Store the context, and call context.unsubscribe() to release the socket when done listening.
+ }
+ else {
+ // change is the changed row
+ // heartbeats are filtered out
+ }
+};
+
+// These are the defaults
+const parameters = { 
+ feed: 'continuous',
+ heartbeat: true,
+ since: 'now'
+};
+
+couch.changes(dbName, mangoQuery, parameters, callback, 'selector', selectorFilter).then(({data, headers, status}) => {
+ // data is json response
+ // headers is an object with all response headers
+ // status is statusCode number
+}, err => {
+ // either request error occured
+ // ...or err.code=EDOCMISSING if document is missing
+ // ...or err.code=EUNKNOWN if statusCode is unexpected
+});
+```
+
 ## Insert a document
 ```javascript
 couch.insert("databaseName", {

lib/node-couchdb.js

@@ -29,6 +29,7 @@ export default class NodeCouchDB {
 
  this._baseUrl = `${instanceOpts.protocol}://${instanceOpts.host}:${instanceOpts.port}`;
  this._cache = instanceOpts.cache;
+ this._auth = instanceOpts.auth;
 
  this._requestWrappedDefaults = request.defaults({
  auth: instanceOpts.auth,
@@ -240,6 +241,46 @@ export default class NodeCouchDB {
  });
  }
 
+ /**
+ * Trigger a design update script in CouchDB. Returns a promise which is
+ * - resolved with {data, headers, status} object
+ * - rejected with `request` original error
+
+ * @param dbName database name
+ * @param id documentId
+ * @param designId design document id
+ * @param updateId update script id
+ * @param data update payload
+ * @returns {*}
+ */
+ design_update(dbName, docId, designId, updateId, data) {
+ if (!docId || !data) {
+ const err = new Error('id and data fields should exist when updating the document');
+ err.code = 'EFIELDMISSING';
+
+ return Promise.reject(err);
+ }
+
+ return this._requestWrapped({
+ method: 'PUT',
+ url: `${this._baseUrl}/${dbName}/_design/${designId}/_update/${updateId}/${encodeURIComponent(docId)}`,
+ body: data
+ }).then(({res, body}) => {
+ this._checkDocumentManipulationStatus(res.statusCode, body)
+
+
+ if (res.statusCode !== 201 && res.statusCode !== 202) {
+ throw new RequestError('EUNKNOWN', `Unexpected status code while inserting document into the database: ${res.statusCode}`, body);
+ }
+
+ return {
+ data: body,
+ headers: res.headers,
+ status: res.statusCode
+ };
+ });
+ }
+
  /**
  * Delete a document in the database. Returns a promise which is
  * - resolved with {data, headers, status} object
@@ -325,6 +366,55 @@ export default class NodeCouchDB {
  });
  }
 
+ /**
+ * Subscribes to the _changes endpoint. The default query params are to feed=continuous, timeout=Infinite, heartbeat=true, since=now
+ * @param dbName
+ * @param query
+ * @param changesCallback receives changes as JSON objects.
+ * This method will initially be called with a null change and a valid context.
+ * This initial callback will occur before any received data from CouchDB
+ * The context object has an unsubscribe() method needed for closing the connection and releasing resources.
+ * @returns {Promise.<TResult>}
+ */
+ changes(dbName, query, changesCallback, changesFilter, changesFilterData) {
+ for (let prop in query) {
+ if (KEYS_TO_ENCODE.includes(prop)) {
+ query[prop] = JSON.stringify(query[prop]);
+ }
+ }
+
+ const requestOpts = {
+ url: `${this._baseUrl}/${dbName}/_changes`,
+ qs: query,
+ auth: this._requestWrappedDefaults.auth,
+ changesCallback
+ };
+
+ if (!changesFilter) {
+ requestOpts.method = 'GET';
+ } else {
+ requestOpts.method = 'POST';
+ requestOpts.body = changesFilterData
+ }
+
+ return this._requestWrapped(requestOpts)
+ .then(({res, body}) => {
+ if (res.statusCode === 404) {
+ throw new RequestError('EDOCMISSING', 'Document is not found', body);
+ }
+
+ if (res.statusCode !== 200 && res.statusCode !== 304) {
+ throw new RequestError('EUNKNOWN', `Unexpected status code while fetching documents from the database: ${res.statusCode}`, body);
+ }
+
+ return {
+ data: body,
+ headers: res.headers,
+ status: res.statusCode
+ };
+ });
+ }
+
  /**
  * Get UUIDs for new documents. Returns a promise which is
  * - resolved with array of new unique ids
@@ -378,6 +468,10 @@ export default class NodeCouchDB {
  opts = {url: opts};
  }
 
+ if (opts.changesCallback) {
+ return this._handleChangesRequest(opts);
+ }
+
  const cacheKey = this._getCacheKey(opts);
  const whenCacheChecked = (!this._cache || (opts.method && opts.method !== 'GET'))
  ? Promise.resolve({})
@@ -410,6 +504,73 @@ export default class NodeCouchDB {
  });
  }
 
+ _handleChangesRequest(opts) {
+ return new Promise((resolve, reject) => {
+ const feed = opts.qs.feed || 'continuous';
+ const heartbeat = opts.qs.heartbeat || 'true';
+ const since = opts.qs.since || 'now';
+ const url = `${opts.url}/_changes?feed=${feed}&heartbeat=${heartbeat}&since=${since}`;
+ // request.js was not working in browser, so we use native 
+ var httpRequest = new XMLHttpRequest();
+ httpRequest.open("GET", url, true); // async
+ if (this._auth.user !== undefined){
+ var authorizationBasic = btoa(this._auth.user + ':' + this._auth.pass);
+ httpRequest.setRequestHeader('Authorization', 'Basic ' + authorizationBasic);
+ }
+ httpRequest.setRequestHeader('Accept', 'application/json');
+ httpRequest.onreadystatechange = OnStateChange;
+
+ function OnStateChange() {
+ switch (httpRequest.readyState) {
+ case 1:
+ break;
+ case 2:
+ break;
+ case 3:
+ const json = httpRequest.responseText;
+ json.split('\n')
+ .filter(line => line.length > 0)
+ .forEach(line => {
+ let parsed;
+ try {
+ parsed = JSON.parse(line);
+ } catch (e) {
+ //console.warn(e);
+ return;
+ }
+ try {
+ opts.changesCallback(parsed, context);
+ } catch (e) {
+ console.warn(e);
+ }
+ });
+ break;
+ case 4:
+ break;
+ default:
+ break;
+ };
+ }
+ httpRequest.send(null);
+
+ const context = {
+ unsubscribe: function () {
+ httpRequest.abort();
+ //BUG request.js not working in browser
+ //req.abort();
+ }
+ };
+ opts.changesCallback(null, context);
+ resolve({
+ res: {
+ statusCode: 200,
+ headers: []
+ },
+ body: '',
+ });
+ }); 
+ }
+
 
  /**
  * Gets cache key built from request options

test/test.js

@@ -48,7 +48,7 @@ describe('node-couchdb tests', () => {
  for (let method of [
  'useCache',
  'listDatabases', 'createDatabase', 'dropDatabase',
- 'insert', 'update', 'del', 'get', 'mango',
+ 'insert', 'update', 'del', 'get', 'mango', 'changes',
  'uniqid'
  ]) {
  assert.typeOf(couch[method], 'function', `instance[${method}] is not a function`);