Fixing custom event sending bug

Author: dhaval24

CHANGELOG.md

@@ -1,7 +1,10 @@
 # CHANGELOG
 
 ## Version 1.0.10
-- Fixed Request Telemetry Sending bug with new schema
+- Fix issue of sending custom event.
+- Method `sanitizeStringForJSON` takes string input and converts it to JSON friendly string.
+- Class `com.microsoft.applicationinsights.common.SanitizationUtils` has methods to sanitize string for JSON.
+- Fixed Request Telemetry Sending bug with new schema.
 - Schema updated to the latest version. Changes in internal namespace `core/src/main/java/com/microsoft/applicationinsights/internal/schemav2`.
 - Class `SendableData` in internal namespace deleted.
 - Class `com.microsoft.applicationinsights.telemetry.BaseSampleSourceTelemetry` takes generic class qualifier `Domain` instead of `SendableData`.

core/src/main/java/com/microsoft/applicationinsights/common/SanitizationUtils.java

@@ -0,0 +1,54 @@
+package com.microsoft.applicationinsights.common;
+
+import java.text.StringCharacterIterator;
+
+/**
+ * Created by dhdoshi on 09/10/2017
+ *
+ * This class provides utility functions to sanitize strings
+ * for various formats. Currently it supports JSON sanitization
+ */
+public final class SanitizationUtils {
+
+    /**
+     * This method appends escape characters to input String to prevent
+     * JSON Sanitization failure
+     * @param text
+     * @return Sanitized String suitable for JSON
+     */
+    public static String sanitizeStringForJSON(String text) {
+
+        final StringBuilder result = new StringBuilder();
+        StringCharacterIterator iterator = new StringCharacterIterator(text);
+        for (char curr = iterator.current(); curr != iterator.DONE; curr = iterator.next()) {
+            if( curr == '\"' ){
+                result.append("\\\"");
+            }
+            else if(curr == '\\'){
+                result.append("\\\\");
+            }
+            else if(curr == '/'){
+                result.append("\\/");
+            }
+            else if(curr == '\b'){
+                result.append("\\b");
+            }
+            else if(curr == '\f'){
+                result.append("\\f");
+            }
+            else if(curr == '\n'){
+                result.append("\\n");
+            }
+            else if(curr == '\r'){
+                result.append("\\r");
+            }
+            else if(curr == '\t'){
+                result.append("\\t");
+            }
+            else {
+                result.append(curr);
+            }
+        }
+        return result.toString();
+    }
+}

core/src/main/java/com/microsoft/applicationinsights/telemetry/JsonTelemetryDataSerializer.java

@@ -29,6 +29,7 @@
 
 import com.google.common.base.Strings;
 
+import com.microsoft.applicationinsights.common.SanitizationUtils;
 import com.microsoft.applicationinsights.internal.schemav2.*;
 import com.microsoft.applicationinsights.internal.util.LocalStringsUtils;
 
@@ -273,8 +274,9 @@ private <T> void write(T item) throws IOException {
             {
                 out.write(String.valueOf(item));
             } else {
+                String sanitizedItem = SanitizationUtils.sanitizeStringForJSON(String.valueOf(item));
                 out.write(JSON_COMMA);
-                out.write(String.valueOf(item));
+                out.write(sanitizedItem);
                 out.write(JSON_COMMA);
             }
         }