fix marketplace docs

docs/README_marketplace_flow.md

@@ -0,0 +1,175 @@
+# Quickstart: Marketplace Flow
+
+This batteries-included flow includes metadata, multiple services for one datatoken, and compute-to-data.
+
+It focuses on Alice's experience as a publisher, and Bob's experience as a buyer & consumer. The rest are services used by Alice and Bob.
+
+Here's the steps.
+1. Initialize services
+1. Alice publishes assets for data services (= publishes a datatoken contract and metadata)
+1. Alice mints 100 tokens
+1. Alice allows marketplace to sell her datatokens
+1. Marketplace posts asset for sale
+1. Value swap: Bob buys datatokens from marketplace
+1. Bob uses a service he just purchased (download)
+
+Let's go through each step.
+
+## 0. Installation
+
+If you haven't installed yet:
+```bash
+npm i @oceanprotocol/lib
+```
+
+## 1. Initialize services
+
+This quickstart treats the publisher service, ganache-cli, metadata store, and marketplace as 
+externally-run services. For convenience, we run barge locally in default settings.
+
+```bash
+git clone https://github.com/oceanprotocol/barge.git
+cd barge/
+git checkout v3
+export PROVIDER_VERSION=phase2
+./start_ocean.sh --no-dashboard
+```
+
+## 2. Alice publishes assets for data services (= publishes a datatoken contract)
+
+1. Create DataToken 
+```javascript
+import { TestContractHandler } from '../TestContractHandler'
+import { DataTokens } from '../../src/datatokens/Datatokens'
+import { Ocean } from '../../src/ocean/Ocean'
+const Web3 = require('web3')
+const web3 = new Web3('http://127.0.0.1:8545')
+const factory = require('@oceanprotocol/contracts/artifacts/development/Factory.json')
+const datatokensTemplate = require('@oceanprotocol/contracts/artifacts/development/DataTokenTemplate.json')
+
+// Alice's config
+const config = {
+    metadataStoreUri: 'http://aquarius:5000',
+    providerUri: 'http://localhost:8030',
+    nodeUri: `http://localhost:${process.env.ETH_PORT || 8545}`,
+    verbose: LogLevel.Error,
+    web3Provider: web3,
+    factoryAddress: '0x123456789...'
+} 
+const ocean = await Ocean.getInstance(config)
+const alice = (await ocean.accounts.list())[0]
+
+datatoken = new DataTokens(
+                config.factoryAddress,
+                factory.abi,
+                datatokensTemplate.abi,
+                web3
+            )
+const data = { t: 1, url: ocean.config.metadataStoreUri }
+const blob = JSON.stringify(data)
+
+const dataTokenAddress = await datatoken.create(blob, alice.getId())
+
+```
+2. Publish asset(s)
+
+```javascript
+const asset = {
+                main: {
+                    type: 'dataset',
+                    name: 'test-dataset',
+                    dateCreated: new Date(Date.now()).toISOString().split('.')[0] + 'Z', // remove milliseconds
+                    author: 'oceanprotocol-team',
+                    license: 'MIT',
+                    files: [
+                        {
+                            url:
+                                'https://raw.githubusercontent.com/tbertinmahieux/MSongsDB/master/Tasks_Demos/CoverSongs/shs_dataset_test.txt',
+                            checksum: 'efb2c764274b745f5fc37f97c6b0e761',
+                            contentLength: '4535431',
+                            contentType: 'text/csv',
+                            encoding: 'UTF-8',
+                            compression: 'zip'
+                        }
+                    ]
+                }
+            }
+
+// create a service
+service1 = await ocean.assets.createAccessServiceAttributes(
+   alice,
+   10, // set the price in datatoken
+   new Date(Date.now()).toISOString().split('.')[0] + 'Z', // publishedDate
+   0 // timeout
+)
+
+// publish asset
+const ddo = await ocean.assets.create(asset, alice, [downloadService], dataTokenAddress)
+
+const did = ddo.id
+```
+
+## 3. Alice mints 100 tokens
+
+```javascript
+await datatoken.mint(tokenAddress, alice.getId(), 100)
+```
+
+## 4. Alice allows marketplace to sell her datatokens
+
+```javascript
+await datatoken.approve(
+   dataTokenAddress,
+   '0x068ed00cf0441e4829d9784fcbe7b9e26d4bd8d0', // marketplace address,
+   20, // marketplaceAllowance
+   alice.getId()
+)
+```
+
+## 5. Marketplace posts asset for sale
+Now, you're the marketplace:)
+
+```javascript
+
+// Market's config
+const marketOcean = await Ocean.getInstance(config)
+const marketplace = (await ocean.accounts.list())[1]
+
+const asset = await ocean.assets.resolve(ddo.id)
+const accessService = await ocean.assets.getServiceByType(asset.id, 'access')
+price = 20 // in USD per dataToken
+assert(accessService.attributes.main.cost * price === 200)
+```
+
+## 6. Value swap: Bob buys datatokens from marketplace
+
+```javascript
+// Not shown: in marketplace GUI, Bob uses Stripe to send USD to marketplace (or other methods / currencies).
+
+```
+   
+## 7. Bob uses a service he just purchased (download)
+Now, you're Bob:)
+
+```javascript
+const accessService = await ocean.assets.getServiceByType(asset.id, 'access')
+const bob = (await ocean.accounts.list())[2]
+await ocean.assets.order(ddo.id, accessService.type, bob.getId()).then(async (res: string) => {
+   res = JSON.parse(res)
+   return await datatoken.transfer(
+      res['dataToken'],
+      res['to'],
+      res['numTokens'],
+      res['from']
+      )
+   }).then(async (tx) => {
+      await ocean.assets.download(
+         ddo.id,
+         tx.transactionHash,
+         dataTokenAddress,
+         bob,
+         '~/my-datasets'
+      )
+   })
+
+```