Add JSON stream fs support #99

Author: wkh237

src/index.js

@@ -16,6 +16,7 @@ import type {
   RNFetchBlobStream,
   RNFetchBlobResponseInfo
 } from './types'
+import URIUtil from './utils/uri'
 import StatefulPromise from './class/StatefulPromise.js'
 import fs from './fs'
 import getUUID from './utils/uuid'
@@ -100,6 +101,86 @@ function config (options:RNFetchBlobConfig) {
   return { fetch : fetch.bind(options) }
 }
 
+/**
+ * Fetch from file system, use the same interface as RNFB.fetch
+ * @param  {RNFetchBlobConfig} [options={}] Fetch configurations
+ * @param  {string} method     Should be one of `get`, `post`, `put`
+ * @param  {string} url        A file URI string
+ * @param  {string} headers    Arguments of file system API
+ * @param  {any} body       Data to put or post to file systen.
+ * @return {Promise}
+ */
+function fetchFile(options = {}, method, url, headers = {}, body):Promise {
+
+  if(!URIUtil.isFileURI(url)) {
+    throw `could not fetch file from an invalid URI : ${url}`
+  }
+
+  url = URIUtil.unwrapFileURI(url)
+
+  let promise = null
+  let cursor = 0
+  let total = -1
+  let cacheData = ''
+  let info = null
+
+  let _progress, _uploadProgress, _stateChange
+
+  switch(method.toLowerCase()) {
+
+    case 'post':
+    break
+
+    case 'put':
+    break
+
+    // read data from file system
+    default:
+      promise = fs.stat(url)
+      .then((stat) => {
+        total = stat.size
+        return fs.readStream(url, headers.encoding || 'utf8', Math.floor(headers.bufferSize) || 4096)
+      })
+      .then((stream) => new Promise((resolve, reject) => {
+        stream.open()
+        info = {
+          state : "2",
+          headers : { 'source' : 'system-fs' },
+          status : 200,
+          respType : 'text',
+          rnfbEncode : headers.encoding || 'utf8'
+        }
+        _stateChange(info)
+        stream.onData((chunk) => {
+          _progress && _progress(cursor, total, chunk)
+          if(headers.noCache)
+            return
+          cacheData += chunk
+        })
+        stream.onError((err) => { reject(err) })
+        stream.onEnd(() => {
+          resolve(new FetchBlobResponse(null, info, cacheData))
+        })
+      }))
+    break
+  }
+
+  promise.progress = (fn) => {
+    _progress = fn
+    return promise
+  }
+  promise.stateChange = (fn) => {
+    _stateChange = fn
+    return promise
+  }
+  promise.uploadProgress = (fn) => {
+    _uploadProgress = fn
+    return promise
+  }
+
+  return promise
+}
+
 /**
  * Create a HTTP request by settings, the `this` context is a `RNFetchBlobConfig` object.
  * @param  {string} method HTTP method, should be `GET`, `POST`, `PUT`, `DELETE`
@@ -119,9 +200,15 @@ function fetch(...args:any):Promise {
   let options = this || {}
   let subscription, subscriptionUpload, stateEvent
   let respInfo = {}
+  let [method, url, headers, body] = [...args]
+
+  // fetch from file system
+  if(URIUtil.isFileURI(url)) {
+    return fetchFile(options, method, url, headers, body)
+  }
 
+  // from remote HTTP(S)
   let promise = new Promise((resolve, reject) => {
-    let [method, url, headers, body] = [...args]
     let nativeMethodName = Array.isArray(body) ? 'fetchBlobForm' : 'fetchBlob'
 
     // on progress event listener

src/json-stream.js

@@ -1,15 +1,38 @@
 import Oboe from './lib/oboe-browser.min.js'
 import XMLHttpRequest from './polyfill/XMLHttpRequest'
+import URIUtil from './utils/uri'
 
 const OboeExtended = (arg: string | object) => {
-  
-  window.XMLHttpRequest = XMLHttpRequest
+
+
   window.location = ''
 
-  if(typeof arg === 'string')
-    arg = 'JSONStream://' + arg
-  else if(typeof arg === 'object')
-    arg = Object.assign(arg, { url : 'JSONStream://' + arg.url })
+  if(!window.XMLHttpRequest.isRNFBPolyfill ) {
+    window.XMLHttpRequest = XMLHttpRequest
+    console.warn('Use JSONStream will automatically replace window.XMLHttpRequest with RNFetchBlob.polyfill.XMLHttpRequest. You are seeing this warning because you did not replace it maually.')
+  }
+
+  if(typeof arg === 'string') {
+    if(URIUtil.isFileURI(arg)) {
+      arg = {
+        url : 'JSONStream://' + arg,
+        headers : { noCache : true }
+      }
+    }
+    else
+      arg = 'JSONStream://' + arg
+
+  }
+  else if(typeof arg === 'object') {
+    let headers = arg.headers || {}
+    if(URIUtil.isFileURI(arg.url)) {
+      headers.noCache = true
+    }
+    arg = Object.assign(arg, {
+      url : 'JSONStream://' + arg.url,
+      headers
+    })
+  }
   return Oboe(arg)
 }