EIP-1102: add isEnabled convenience method to provider

app/scripts/contentscript.js

@@ -116,16 +116,25 @@ function setupStreams () {
  * handles posting these messages automatically.
  */
 function listenForProviderRequest () {
-  window.addEventListener('message', (event) => {
-    if (event.source !== window) { return }
-    if (!event.data || !event.data.type || event.data.type !== 'ETHEREUM_ENABLE_PROVIDER') { return }
+  window.addEventListener('message', ({ source, data }) => {
+    if (source !== window || !data || !data.type) { return }
+    switch (data.type) {
+      case 'ETHEREUM_ENABLE_PROVIDER':
         extension.runtime.sendMessage({
           action: 'init-provider-request',
-      origin: event.source.location.hostname,
+          origin: source.location.hostname,
         })
+        break
+      case 'ETHEREUM_PROVIDER_STATUS':
+        extension.runtime.sendMessage({
+          action: 'provider-status-request',
+          origin: source.location.hostname,
+        })
+        break
+    }
   })
 
-  extension.runtime.onMessage.addListener(({ action }) => {
+  extension.runtime.onMessage.addListener(({ action, isEnabled }) => {
     if (!action) { return }
     switch (action) {
       case 'approve-provider-request':
@@ -142,6 +151,9 @@ function listenForProviderRequest () {
           })
         })
         break
+      case 'provider-status':
+        injectScript(`window.dispatchEvent(new CustomEvent('ethereumproviderstatus', { detail: { isEnabled: ${isEnabled}}}))`)
+        break
     }
   })
 }

app/scripts/controllers/provider-approval.js

@@ -18,7 +18,15 @@ class ProviderApprovalController {
     this.publicConfigStore = publicConfigStore
     this.approvedOrigins = {}
     platform && platform.addMessageListener && platform.addMessageListener(({ action, origin }) => {
-      action && action === 'init-provider-request' && this.handleProviderRequest(origin)
+      if (!action) { return }
+      switch (action) {
+        case 'init-provider-request':
+          this.handleProviderRequest(origin)
+          break
+        case 'provider-status-request':
+          this.handleProviderStatusRequest(origin)
+          break
+      }
     })
   }
 
@@ -36,6 +44,16 @@ class ProviderApprovalController {
     this.openPopup && this.openPopup()
   }
 
+  /**
+   * Called by a tab to detemrine if a full Ethereum provider API is exposed
+   *
+   * @param {string} origin - Origin of the window requesting provider status
+   */
+  async handleProviderStatusRequest (origin) {
+    const isEnabled = await this.isApproved(origin)
+    this.platform && this.platform.sendMessage({ action: 'provider-status', isEnabled }, { active: true })
+  }
+
   /**
    * Called when a user approves access to a full Ethereum provider API
    *

app/scripts/inpage.js

@@ -50,6 +50,19 @@ inpageProvider.enable = function () {
   })
 }
 
+inpageProvider.isEnabled = function () {
+  return new Promise((resolve, reject) => {
+    window.addEventListener('ethereumproviderstatus', ({ detail }) => {
+      if (typeof detail.error !== 'undefined') {
+        reject(detail.error)
+      } else {
+        resolve(detail.isEnabled)
+      }
+    })
+    window.postMessage({ type: 'ETHEREUM_PROVIDER_STATUS' }, '*')
+  })
+}
+
 // Work around for web3@1.0 deleting the bound `sendAsync` but not the unbound
 // `sendAsync` method on the prototype, causing `this` reference issues with drizzle
 const proxiedInpageProvider = new Proxy(inpageProvider, {
@@ -60,6 +73,7 @@ const proxiedInpageProvider = new Proxy(inpageProvider, {
 
 window.ethereum = proxiedInpageProvider
 
+
 //
 // setup web3
 //