Support arithmetic expressions in the JSON generator

x4base · May 5, 2016 · 95a2c1e · 95a2c1e
1 parent 48d78c5
commit 95a2c1e
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Showing 4 changed files with 87 additions and 23 deletions.
diff --git a/caravel/assets/javascripts/datasource.js b/caravel/assets/javascripts/datasource.js
@@ -1,19 +1,32 @@
+var $ = window.$ || require('jquery');
 var jsonGenerator = require("./modules/json_generator");
 
 $(document).ready(function () {
+    var $modal = $('#json_gen_modal');
     $('#convertButton').click(function () {
         var expression = $('#expression').val().trim();
-        var parse_tree = jsonGenerator.parse(expression);
-        console.log(parse_tree);
-        $('#json').val(JSON.stringify(parse_tree));
-        $(this).closest('.modal').modal('hide');
+        var $alert = $modal.find('#errorMsg');
+        $alert
+            .removeClass('hidden')
+            .hide()
+            .html("");
+        try {
+            var parse_tree = jsonGenerator.parse(expression);
+            $('#json').val(JSON.stringify(parse_tree));
+
+            $(this).closest('.modal').modal('hide');
+        } catch (e) {
+            $alert
+                .show()
+                .html(e.message);
+        }
     });
-    $('#json_gen_modal').on('shown.bs.modal', function () {
+    $modal.on('shown.bs.modal', function () {
         $('#expression').focus();
     });
 
     var showJsonGenModal = function () {
-        $('#json_gen_modal').modal('show');
+        $modal.modal('show');
     };
 
     $.extend(window, {

diff --git a/caravel/assets/javascripts/modules/json_generator.js b/caravel/assets/javascripts/modules/json_generator.js
@@ -1,21 +1,16 @@
 var jsep = require("jsep");
 
-var typeMap = {
-    sum: 'doubleSum',
-    doubleSum: 'doubleSum',
-    longSum: 'longSum',
-};
-
-var capitalize = function (string) {
-    return string.charAt(0).toUpperCase() + string.slice(1);
+var capitalize = function (str) {
+    return str.charAt(0).toUpperCase() + str.slice(1);
 };
 
 var convertFuncCall = function (node) {
     var funcName = node.callee.name;
-    var fieldName = node.arguments[0].name;
-    if (!funcName) return;
+    var fieldName = node.arguments[0].name || "";
     var m = funcName.toLowerCase().match(/^(double|long)?(sum|min|max)$/);
-    if (!m) return;
+    if (!m) {
+        throw new Error("Unsupported function call: " + funcName);
+    }
 
     var varType = m[1] || 'double'; // default to double
     var funcType = m[2];
@@ -25,15 +20,68 @@ var convertFuncCall = function (node) {
     return {
         type: type,
         name: fieldName,
-        fieldName: fieldName,
+        fieldName: fieldName
+    };
+};
+
+var convertField = function (node) {
+    var fieldName = node.name;
+    return {
+        type: "fieldAccess",
+        name: fieldName,
+        fieldName: fieldName
+    };
+};
+
+var convertBinary = function (node) {
+    var op = node.operator;
+    // TODO: Support the "quotient" type
+    if (!/[+\-*\/]/.test(op)) {
+        throw new Error("Unsupported operation: " + op);
+    }
+    return {
+        type: "arithmetic",
+        fn: op,
+        fields: [node.left, node.right].map(function (child) {
+            return convertArithmetic(child);
+        })
+    };
+};
+
+var convertLiteral = function (node) {
+    return {
+        type: "constant",
+        value: node.value
     };
 };
 
+var arithmeticTokenHandler = {
+    Identifier: convertField,
+    BinaryExpression: convertBinary,
+    Literal: convertLiteral
+};
+
+var convertArithmetic = function (node) {
+    var converter = arithmeticTokenHandler[node.type];
+    if (!converter) {
+        throw new Error("Invalid Expression (" + node.type + ")");
+    }
+    return converter(node);
+};
+
 var parse = function (expression) {
-    expression = expression.trim();
+    expression = expression.trim().replace('\n', '');
     var parse_tree = jsep(expression);
-    parse_tree = convertFuncCall(parse_tree);
-    return parse_tree;
+    var converterMap = {
+        CallExpression: convertFuncCall,
+        BinaryExpression: convertArithmetic,
+        Literal: convertArithmetic
+    };
+    var converter = converterMap[parse_tree.type];
+    if (!converter) {
+        throw new Error("Invalid Expression (" + parse_tree.type + ")");
+    }
+    return converter(parse_tree);
 };
 
 module.exports = {

diff --git a/caravel/templates/caravel/models/datasource/edit.html b/caravel/templates/caravel/models/datasource/edit.html
@@ -8,10 +8,14 @@
                 <div class="modal-header">
                     <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
                     <h4 class="modal-title" id="myModalLabel">JSON Generator</h4>
-                    <h6><strong>Enter the algebraic expression to convert. E.g. longSum(price), doubleMin(price)</strong></h6>
+                    <p>Enter the algebraic expression to convert. For example: <br>
+                        <strong>Normal metrics</strong>: longSum(price), doubleMin(price)<br>
+                        <strong>Post Aggregation</strong>: (price/count)*100<br>
+                    </p>
                 </div>
                 <div class="modal-body">
                     <textarea id="expression" rows="5" cols="60"></textarea>
+                    <div class="alert alert-danger hidden" id="errorMsg"></div>
                 </div>
                 <div class="modal-footer">
                     <button type="button" class="btn btn-default" data-dismiss="modal">

diff --git a/caravel/views.py b/caravel/views.py
@@ -181,7 +181,6 @@ class DruidMetricInlineView(CompactCRUDMixin, CaravelModelView):  # noqa
             "[Druid Post Aggregation]"
             "(http://druid.io/docs/latest/querying/post-aggregations.html)",
             True),
-        # 'json': Markup("<a href='javascript:showJsonGenModal()'>Json Generator</a>")
         'json': utils.markdown(
             "You can also use the [generator](javascript:showJsonGenModal()) to generate json",
             True),