Add a simple interface to enable custom buffer storage solutions micr…

…osoft#1419

This can be used like:

```
const appInsights = new ApplicationInsights({
  config: {
    enableSessionStorageBuffer: true,
    bufferOverride: {
      getItem: (logger, key) => localStorage.getItem(key),
      setItem: (logger, key, value) => localStorage.setItem(key, value),
    }
  }
});
```

channels/applicationinsights-channel-js/src/Interfaces.ts

@@ -1,3 +1,5 @@
+import { IStorageBuffer } from "@microsoft/applicationinsights-common";
+
 export interface ISenderConfig {
  /**
  * The url to which payloads will be sent
@@ -29,6 +31,11 @@ export interface ISenderConfig {
  */
  enableSessionStorageBuffer: () => boolean;
 
+ /**
+ * Specify the storage buffer type implementation.
+ */
+ bufferOverride: () => IStorageBuffer | false;
+
  /**
  * Is retry handler disabled.
  * If enabled, retry on 206 (partial success), 408 (timeout), 429 (too many requests), 500 (internal server error) and 503 (service unavailable).

channels/applicationinsights-channel-js/src/SendBuffer.ts

@@ -198,6 +198,7 @@ export class SessionStorageSendBuffer extends BaseSendBuffer implements ISendBuf
  constructor(logger: IDiagnosticLogger, config: ISenderConfig) {
  super(logger, config);
  let _bufferFullMessageSent = false;
+ const { getItem, setItem } = config.bufferOverride() || { getItem: utlGetSessionStorage, setItem: utlSetSessionStorage };
 
  dynamicProto(SessionStorageSendBuffer, this, (_self, _base) => {
  const bufferItems = _getBuffer(SessionStorageSendBuffer.BUFFER_KEY);
@@ -287,7 +288,7 @@ export class SessionStorageSendBuffer extends BaseSendBuffer implements ISendBuf
  let prefixedKey = key;
  try {
  prefixedKey = config.namePrefix && config.namePrefix() ? config.namePrefix() + "_" + prefixedKey : prefixedKey;
- const bufferJson = utlGetSessionStorage(logger, prefixedKey);
+ const bufferJson = getItem(logger, prefixedKey);
  if (bufferJson) {
  let buffer: string[] = getJSON().parse(bufferJson);
  if (isString(buffer)) {
@@ -314,11 +315,11 @@ export class SessionStorageSendBuffer extends BaseSendBuffer implements ISendBuf
  try {
  prefixedKey = config.namePrefix && config.namePrefix() ? config.namePrefix() + "_" + prefixedKey : prefixedKey;
  const bufferJson = JSON.stringify(buffer);
- utlSetSessionStorage(logger, prefixedKey, bufferJson);
+ setItem(logger, prefixedKey, bufferJson);
  } catch (e) {
  // if there was an error, clear the buffer
  // telemetry is stored in the _buffer array so we won't loose any items
- utlSetSessionStorage(logger, prefixedKey, JSON.stringify([]));
+ setItem(logger, prefixedKey, JSON.stringify([]));
 
  _throwInternal(logger, eLoggingSeverity.WARNING,
  _eInternalMessageId.FailedToSetStorageBuffer,

channels/applicationinsights-channel-js/src/Sender.ts

@@ -52,6 +52,7 @@ function _getDefaultAppInsightsChannelConfig(): ISenderConfig {
  maxBatchSizeInBytes: () => 102400, // 100kb
  disableTelemetry: () => false,
  enableSessionStorageBuffer: () => true,
+ bufferOverride: () => false,
  isRetryDisabled: () => false,
  isBeaconApiDisabled: () => true,
  disableXhr: () => false,
@@ -231,8 +232,11 @@ export class Sender extends BaseTelemetryPlugin implements IChannelControlsAI {
  }
  });
 
- _self._buffer = (_self._senderConfig.enableSessionStorageBuffer() && utlCanUseSessionStorage())
- ? new SessionStorageSendBuffer(diagLog, _self._senderConfig) : new ArraySendBuffer(diagLog, _self._senderConfig);
+ const useSessionStorage = _self._senderConfig.enableSessionStorageBuffer() &&
+ (_self._senderConfig.bufferOverride() || utlCanUseSessionStorage())
+ _self._buffer = useSessionStorage
+ ? new SessionStorageSendBuffer(diagLog, _self._senderConfig)
+ : new ArraySendBuffer(diagLog, _self._senderConfig);
  _self._sample = new Sample(_self._senderConfig.samplingPercentage(), diagLog);
 
  if(!_validateInstrumentationKey(config)) {

shared/AppInsightsCommon/src/Interfaces/IConfig.ts

@@ -3,6 +3,7 @@
 import { IConfiguration, ICustomProperties, isNullOrUndefined } from "@microsoft/applicationinsights-core-js";
 import { DistributedTracingModes } from "../Enums";
 import { IRequestContext } from "./IRequestContext";
+import { IStorageBuffer } from "./IStorageBuffer";
 
 /**
  * Configuration settings for how telemetry is sent
@@ -170,6 +171,11 @@ export interface IConfig {
  */
  enableSessionStorageBuffer?: boolean;
 
+ /**
+ * If specified, overrides the storage & retrieval mechanism that is used to manage unsent telemetry.
+ */
+ bufferOverride?: IStorageBuffer;
+
  /**
  * @deprecated Use either disableCookiesUsage or specify a cookieCfg with the enabled value set.
  * If true, the SDK will not store or read any data from cookies. Default is false. As this field is being deprecated, when both

shared/AppInsightsCommon/src/Interfaces/IStorageBuffer.ts

@@ -0,0 +1,13 @@
+import { IDiagnosticLogger } from "@microsoft/applicationinsights-core-js";
+
+export interface IStorageBuffer {
+ /**
+ * Retrieves the stored value for a given key
+ */
+ getItem(logger: IDiagnosticLogger, name: string): string;
+
+ /**
+ * Sets the stored value for a given key
+ */
+ setItem(logger: IDiagnosticLogger, name: string, data: string): boolean;
+}

shared/AppInsightsCommon/src/applicationinsights-common.ts

@@ -34,6 +34,7 @@ export { PageViewPerformance } from "./Telemetry/PageViewPerformance";
 export { Data } from "./Telemetry/Common/Data";
 export { eSeverityLevel, SeverityLevel } from "./Interfaces/Contracts/SeverityLevel";
 export { IConfig, ConfigurationManager } from "./Interfaces/IConfig";
+export { IStorageBuffer } from "./Interfaces/IStorageBuffer";
 export { IChannelControlsAI } from "./Interfaces/IChannelControlsAI";
 export { IContextTagKeys, ContextTagKeys } from "./Interfaces/Contracts/ContextTagKeys";
 export {