load npm module from unpkg

apps/remix-ide-e2e/src/tests/debugger.test.ts

@@ -92,10 +92,10 @@ module.exports = {
     .waitForElementVisible('#stepdetail')
     .goToVMTraceStep(10)
     .getEditorValue((content) => {
+      console.log(content)
       browser.assert.ok(content.indexOf(`constructor (string memory name_, string memory symbol_) {
         _name = name_;
         _symbol = symbol_;
-        _decimals = 18;
     }`) != -1, 
     'current displayed content is not from the ERC20 source code')
     })        

apps/remix-ide-e2e/src/tests/solidityImport.test.ts

@@ -78,8 +78,18 @@ module.exports = {
           .getEditorValue((content) => {
             browser.assert.ok(content.indexOf(`contract ERC20 is Context, IERC20`) != -1, 
           'current displayed content should be from the ERC20 source code')
-          })     
-          .end()          
+          })
+  },
+
+  'Test NPM Import (with unpkg.com)': function (browser: NightwatchBrowser) {
+    browser
+          // .setSolidityCompilerVersion('soljson-v0.8.0+commit.c7dfd78e.js')
+          .clickLaunchIcon('fileExplorers')
+          .click('li[data-id="treeViewLitreeViewItembrowser/README.txt"')
+          .addFile('Untitled9.sol', sources[8]['browser/Untitled9.sol'])
+          .clickLaunchIcon('fileExplorers')
+          .verifyContracts(['test13', 'ERC20', 'SafeMath'], {wait: 30000})
+          .end()       
   },
   tearDown: sauce
 }
@@ -109,5 +119,8 @@ const sources = [
   },
   {
     'browser/Untitled8.sol': {content: 'import "https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-contracts/master/contracts/token/ERC20/ERC20.sol"; contract test12 {}'}
+  },
+  {
+    'browser/Untitled9.sol': {content: 'pragma solidity >=0.6.0 <0.8.0; import "@openzeppelin/contracts/token/ERC20/ERC20.sol"; contract test13 {}'}
   }
 ]

apps/remix-ide/src/app/compiler/compiler-imports.js

@@ -6,7 +6,6 @@ const remixTests = require('@remix-project/remix-tests')
 const globalRegistry = require('../../global/registry')
 const addTooltip = require('../ui/tooltip')
 const async = require('async')
-var resolver = require('@resolver-engine/imports').ImportsEngine()
 
 const profile = {
   name: 'contentImport',
@@ -50,7 +49,7 @@ module.exports = class CompilerImports extends Plugin {
     })
   }
 
-  import (url, force, loadingCb, cb) {
+  async import (url, force, loadingCb, cb) {
     if (typeof force !== 'boolean') {
       const temp = loadingCb
       loadingCb = force
@@ -66,44 +65,20 @@ module.exports = class CompilerImports extends Plugin {
     if (imported) {
       return cb(null, imported.content, imported.cleanUrl, imported.type, url)
     }
-    var handlers = this.urlResolver.getHandlers()
-    var found = false
-    handlers.forEach(function (handler) {
-      if (found) return
-      var match = handler.match(url)
-      if (match) {
-        found = true
-        loadingCb('Loading ' + url + ' ...')
-        handler.handle(match).then(function (result) {
-          const { content, cleanUrl } = result
-          self.previouslyHandled[url] = {
-            content,
-            cleanUrl,
-            type: handler.type
-          }
-          cb(null, content, cleanUrl, handler.type, url)
-        }).catch(function (error) {
-          cb('Unable to import url : ' + error)
-        })
-      }
-    })
-    if (found) return
 
-    resolver
-      .resolve(url)
-      .then(result => {
-        return resolver.require(url)
-      })
-      .then(result => {
-        if (url.indexOf(result.provider + ':') === 0) {
-          url = url.substring(result.provider.length + 1) // remove the github prefix
-        }
-        cb(null, result.source, url, result.provider, result.url)
-      })
-      .catch(err => {
-        console.error(err)
-        cb('Unable to import "' + url + '": File not found')
-      })
+    let resolved
+    try {
+      resolved = await this.urlResolver.resolve(url)
+      const { content, cleanUrl, type } = resolved
+      self.previouslyHandled[url] = {
+        content,
+        cleanUrl,
+        type
+      }
+      cb(null, content, cleanUrl, type, url)
+    } catch (e) {
+      return cb('Unable to import url : ' + e.message)
+    }
   }
 
   importExternal (url, targetPath, cb) {
@@ -182,13 +157,12 @@ module.exports = class CompilerImports extends Plugin {
               }
               resolve(result)
             })
-          } else {
-            // try to resolve external content
-            this.importExternal(url, targetPath, (error, content) => {
-              if (error) return reject(error)
-              resolve(content)
-            })
           }
+
+          this.importExternal(url, targetPath, (error, content) => {
+            if (error) return reject(error)
+            resolve(content)
+          })
         })
       }
     })

libs/remix-url-resolver/src/resolve.ts

@@ -121,6 +121,21 @@ export class RemixURLResolver {
     }
   }
 
+   /**
+  * Handle an import statement based on NPM
+  * @param url The url of the NPM import statement
+  */
+  async handleNpmImport(url: string): Promise<HandlerResponse> {
+    // eslint-disable-next-line no-useless-catch
+    try {
+      const req = 'https://unpkg.com/' + url
+      const response: AxiosResponse = await axios.get(req)
+      return { content: response.data, cleanUrl: url }
+    } catch (e) {
+      throw e
+    }
+  }
+
   getHandlers(): Handler[] {
     return [
       {
@@ -147,6 +162,11 @@ export class RemixURLResolver {
         type: 'ipfs',
         match: (url) => { return /^(ipfs:\/\/?.+)/.exec(url) },
         handle: (match) => this.handleIPFS(match[1])
+      },
+      {
+        type: 'npm',
+        match: (url) => { return /^[^/][^\n"?:*<>|]*$/g.exec(url) }, // match a typical relative path
+        handle: (match) => this.handleNpmImport(match[0])
       }
     ]
   }