New select method via HTTP POST to let user make queries with lot parameters

lib/client.js

@@ -108,7 +108,7 @@ Client.prototype._callSolrServer = function(requestFullPath, fetchOptions, final
 };
 
 /**
- * Request get
+ * Request data (using http get method)
  *
  * @param {String} path - target path
  * @param {Object|String} query - query
@@ -143,6 +143,60 @@ Client.prototype._requestGet = function(path, query, finalCallback) {
   return this._callSolrServer(requestFullPath, options, finalCallback);
 };
 
+/**
+ * Request data (using http post method)
+ *
+ * @param {String} path - target path
+ * @param {Object|String} query - query
+ * @param {Function} finalCallback - (err, result)
+ *
+ * @returns {undefined|Promise} - When there's no callback function it returns a PromiseŰ
+ */
+Client.prototype._requestGetUsingHttpPost = function(path, query, finalCallback) {
+  var params, options, requestUrl;
+
+  if (query instanceof Query) {
+    params = query.toString();
+  } else if (_.isString(query)) {
+    params = query;
+  } else {
+    params = 'q=*:*';
+  }
+  requestUrl = this._makeHostUrl(this.options.protocol, this.options.host, this.options.port);
+  requestUrl += '/' + [this.options.rootPath, this.options.core, path].join('/');
+
+  logger.debug('[_requestGetUsingHttpPost] requestUrl: ', requestUrl, ' params: ', params);
+
+  options = {
+    method: 'POST',
+    body: params,
+    headers: {
+      'accept' : 'application/json; charset=utf-8',
+      'content-type' : 'application/x-www-form-urlencoded; charset=utf-8'
+    }
+  };
+  var result = fetch(requestUrl, options)
+    .then(function(res) {
+      if (res.status !== 200) {
+        logger.error(res);
+        throw new Error('Solr server error: ' + res.status);
+      } else {
+        return res.json();
+      }
+    });
+  if (typeof finalCallback === 'function') {
+    result
+      .then(function(json) {
+        finalCallback(null,json);
+      })
+      .catch(function (err) {
+        finalCallback(err.message);
+      });
+  } else {
+    return result;
+  }
+};
+
 /**
  * Request post
  *
@@ -194,7 +248,7 @@ Client.prototype.query = function() {
 };
 
 /**
- * Search
+ * Search (using HTTP get method)
  *
  * @param {Object|String} query
  * @param {Function} finalCallback - (err, result)
@@ -204,6 +258,22 @@ Client.prototype.query = function() {
 Client.prototype.search = function(query, finalCallback) {
   return this._requestGet(this.SEARCH_PATH, query, finalCallback);
 };
+/**
+ * Search (using HTTP post method)
+ *
+ * @param {Object|String} query
+ * @param {Function} finalCallback - (err, result)
+ *
+ * @returns {Undefined|Promise}
+ */
+Client.prototype.searchUsingHttpPost = function(query, finalCallback) {
+  if (typeof finalCallback === 'function') {
+    this._requestGetUsingHttpPost(this.SEARCH_PATH, query, finalCallback);
+  } else {
+    return this._requestGetUsingHttpPost(this.SEARCH_PATH, query);
+  }
+};
+
 /**
  * Terms
  *