diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7eaf87c..3844d4b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,61 @@
 
+##### 5.0.0
+
+* Update several dependencies, moving some to `optional` and `dev`
+* Update many typescript definitions
+* Added `mime-types` fallback when browser doesn't provide `file.type` [#223]
+
+##### 4.9.3
+
+* Add missing typescript definitions [#216]
+
+##### 4.9.2
+
+* Added typescript definitions
+
+##### 4.9.0
+
+* Better error messaging [#207]
+* Configurable Expires time [#208]
+
+##### 4.8.0
+
+* Allow 201 response code from PUT [#174]
+
+##### 4.7.0
+
+* Add an `onSignedUrl` lifecycle hook [#170]
+
+##### 4.6.2
+
+* Fix `undefined` in file path when not providing `s3path` prop [#160]
+
+##### 4.6.1
+
+* Fix `s3path` and `uniquePrefix` ordering when applied together [#156]
+
+##### 4.6.0
+
+* Add `autoUpload` prop, which can be set to `false` to disable automatic upload [#95] [#107] [#155]
+
+##### 4.5.1
+
+* Add `inputRef` prop [#153]
+
+##### 4.5.0
+
+* Removed `peerDependencies` on react and react-dom [#136]
+
+##### 4.4.0
+
+* Support `getS3` function in bundled router options [#139]
+* Support `s3Path` string prefix prop [#140]
+
+##### 4.3.0
+
+* Support middleware in express module with optional second arg
+* Allow 200 or 201 for success on sign request
+
 ##### 4.2.0
 
 * Switch to `uuid` instead of `node-uuid` [#115]
diff --git a/README.md b/README.md
index 8cde3a5..cd295ff 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,9 @@ var ReactS3Uploader = require('react-s3-uploader');
     signingUrl="/s3/sign"
     signingUrlMethod="GET"
     accept="image/*"
+    s3path="/uploads/"
     preprocess={this.onUploadStart}
+    onSignedUrl={this.onSignedUrl}
     onProgress={this.onUploadProgress}
     onError={this.onUploadError}
     onFinish={this.onUploadFinish}
@@ -30,7 +32,10 @@ var ReactS3Uploader = require('react-s3-uploader');
     uploadRequestHeaders={{ 'x-amz-acl': 'public-read' }}  // this is the default
     contentDisposition="auto"
     scrubFilename={(filename) => filename.replace(/[^\w\d_\-.]+/ig, '')}
-    server="http://cross-origin-server.com" />
+    server="http://cross-origin-server.com"
+    inputRef={cmp => this.uploadInput = cmp}
+    autoUpload={true}
+    />
 ```
 
 The above example shows all supported `props`.
@@ -58,8 +63,7 @@ The resulting DOM is essentially:
 The `preprocess(file, next)` prop provides an opportunity to do something before the file upload begins,
 modify the file (scaling the image for example), or abort the upload by not calling `next(file)`.
 
-When a file is chosen, it will immediately be uploaded to S3.  You can listen for progress (and
-create a status bar, for example) by providing an `onProgress` function to the component.
+When a file is chosen, it will immediately be uploaded to S3 (unless `autoUpload` is `false`).  You can listen for progress (and create a status bar, for example) by providing an `onProgress` function to the component.
 
 ### Extra props
 You can pass any extra props to `<ReactS3Uploader />` and these will be passed down to the final `<input />`. which means that if you give the ReactS3Uploader a className or a name prop the input will have those as well.
@@ -114,6 +118,7 @@ app.use('/s3', require('react-s3-uploader/s3router')({
     bucket: "MyS3Bucket",
     region: 'us-east-1', //optional
     signatureVersion: 'v4', //optional (use for some amazon regions: frankfurt and others)
+    signatureExpires: 60, //optional, number of seconds the upload signed URL should be valid for (defaults to 60)
     headers: {'Access-Control-Allow-Origin': '*'}, // optional
     ACL: 'private', // this is default
     uniquePrefix: true // (4.0.2 and above) default is true, setting the attribute to false preserves the original filename in S3
@@ -124,6 +129,9 @@ This also provides another endpoint: `GET /s3/img/(.*)` and `GET /s3/uploads/(.*
 that provides access to the uploaded file (which are uploaded privately by default).  The
 request is then redirected to the URL, so that the image is served to the client.
 
+If you need to use pass more than region and signatureVersion to S3 instead use the `getS3` param. `getS3` accepts a
+function that returns a new AWS.S3 instance. This is also useful if you want to mock S3 for testing purposes.
+
 **To use this you will need to include the [express module](https://www.npmjs.com/package/express) in your package.json dependencies.**
 
 #### Access/Secret Keys
@@ -178,6 +186,53 @@ respond_to do |format|
 end
 ```
 
+#### [Micro](https://github.com/zeit/micro)
+
+```javascript
+const aws = require('aws-sdk')
+const uuidv4 = require('uuid/v4')
+const { createError } = require('micro')
+
+const options = {
+  bucket: 'S3_BUCKET_NAME',
+  region: 'S3_REGION',
+  signatureVersion: 'v4',
+  ACL: 'public-read'
+}
+
+const s3 = new aws.S3(options)
+
+module.exports = (req, res) => {
+  const originalFilename = req.query.objectName
+
+  // custom filename using random uuid + file extension
+  const fileExtension = originalFilename.split('.').pop()
+  const filename = `${uuidv4()}.${fileExtension}`
+
+  const params = {
+    Bucket: options.bucket,
+    Key: filename,
+    Expires: 60,
+    ContentType: req.query.contentType,
+    ACL: options.ACL
+  }
+
+  const signedUrl = s3.getSignedUrl('putObject', params)
+
+  if (signedUrl) {
+    // you may also simply return the signed url, i.e. `return { signedUrl }`
+    return {
+      signedUrl,
+      filename,
+      originalFilename,
+      publicUrl: signedUrl.split('?').shift()
+    }
+  } else {
+    throw createError(500, 'Cannot create S3 signed URL')
+  }
+}
+```
+
 
 ##### Other Servers
 
diff --git a/ReactS3Uploader.js b/ReactS3Uploader.js
index 080bf5a..4ec64a2 100644
--- a/ReactS3Uploader.js
+++ b/ReactS3Uploader.js
@@ -13,6 +13,7 @@ var ReactS3Uploader = createReactClass({
         signingUrl: PropTypes.string,
         getSignedUrl: PropTypes.func,
         preprocess: PropTypes.func,
+        onSignedUrl: PropTypes.func,
         onProgress: PropTypes.func,
         onFinish: PropTypes.func,
         onError: PropTypes.func,
@@ -29,29 +30,40 @@ var ReactS3Uploader = createReactClass({
         uploadRequestHeaders: PropTypes.object,
         contentDisposition: PropTypes.string,
         server: PropTypes.string,
-        scrubFilename: PropTypes.func
+        scrubFilename: PropTypes.func,
+        s3path: PropTypes.string,
+        inputRef: PropTypes.oneOfType([
+          PropTypes.object,
+          PropTypes.func
+        ]),
+        autoUpload: PropTypes.bool
     },
 
     getDefaultProps: function() {
         return {
             preprocess: function(file, next) {
-                console.log('Pre-process: ' + file.name);
+                console.log('Pre-process: ',file.name);
                 next(file);
             },
-            onProgress: function(percent, message) {
-                console.log('Upload progress: ' + percent + '% ' + message);
+            onSignedUrl: function( signingServerResponse ) {
+                console.log('Signing server response: ', signingServerResponse);
+            },
+            onProgress: function(percent, message, file) {
+                console.log('Upload progress: ',`${percent} % ${message}`);
             },
             onFinish: function(signResult) {
-                console.log("Upload finished: " + signResult.publicUrl)
+                console.log("Upload finished: ",signResult.publicUrl)
             },
             onError: function(message) {
-                console.log("Upload error: " + message);
+                console.log("Upload error: ",message);
             },
             server: '',
             signingUrlMethod: 'GET',
             scrubFilename: function(filename) {
                 return filename.replace(/[^\w\d_\-\.]+/ig, '');
-            }
+            },
+            s3path: '',
+            autoUpload: true
         };
     },
 
@@ -61,6 +73,7 @@ var ReactS3Uploader = createReactClass({
             signingUrl: this.props.signingUrl,
             getSignedUrl: this.props.getSignedUrl,
             preprocess: this.props.preprocess,
+            onSignedUrl: this.props.onSignedUrl,
             onProgress: this.props.onProgress,
             onFinishS3Put: this.props.onFinish,
             onError: this.props.onError,
@@ -71,7 +84,8 @@ var ReactS3Uploader = createReactClass({
             uploadRequestHeaders: this.props.uploadRequestHeaders,
             contentDisposition: this.props.contentDisposition,
             server: this.props.server,
-            scrubFilename: this.props.scrubFilename
+            scrubFilename: this.props.scrubFilename,
+            s3path: this.props.s3path
         });
     },
 
@@ -88,7 +102,18 @@ var ReactS3Uploader = createReactClass({
     },
 
     getInputProps: function() {
-        var temporaryProps = objectAssign({}, this.props, {type: 'file', onChange: this.uploadFile});
+        // declare ref beforehand and filter out
+        // `inputRef` by `ReactS3Uploader.propTypes`
+        var additional = {
+            type: 'file',
+            ref: this.props.inputRef
+        };
+
+        if ( this.props.autoUpload ) {
+            additional.onChange = this.uploadFile;
+        }
+        
+        var temporaryProps = objectAssign({}, this.props, additional);
         var inputProps = {};
 
         var invalidProps = Object.keys(ReactS3Uploader.propTypes);
diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..29b0195
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,77 @@
+declare module 'react-s3-uploader' {
+  import { Component } from 'react';
+
+  export interface S3Response {
+    signedUrl: string;
+    publicUrl: string;
+    filename: string;
+    fileKey: string;
+  }
+
+  export interface ReactS3UploaderProps {
+    signingUrl?: string;
+    signingUrlMethod?: 'GET' | 'POST';
+    getSignedUrl?: (file: File, callback: (params: S3Response) => void) => void;
+    accept?: string;
+    s3path?: string;
+    preprocess?: (file: File, next: (file: File) => void) => void;
+    onSignedUrl?: (response: S3Response) => void;
+    onProgress?: (percent: number, status: string, file: File) => void;
+    onError?: (message: string) => void;
+    onFinish?: (result: S3Response, file: File) => void;
+    signingUrlHeaders?: {
+      additional: object;
+    };
+    signingUrlQueryParams?: {
+      additional: object;
+    };
+    signingUrlWithCredentials?: boolean;
+    uploadRequestHeaders?: object;
+    contentDisposition?: string;
+    server?: string;
+    inputRef?: (ref: HTMLInputElement) => any;
+    autoUpload?: boolean;
+    scrubFilename?: (filename: string) => string;
+    [key: string]: any;
+  }
+
+  class ReactS3Uploader extends Component<ReactS3UploaderProps, unknown> { }
+
+  export default ReactS3Uploader;
+}
+
+declare module 'react-s3-uploader/s3upload' {
+  import { ReactS3UploaderProps, S3Response } from 'react-s3-uploader';
+
+  export interface S3UploadOptions extends Pick<
+    ReactS3UploaderProps,
+    | 'contentDisposition'
+    | 'getSignedUrl'
+    | 'onProgress'
+    | 'onError'
+    | 'onSignedUrl'
+    | 'preprocess'
+    | 's3path'
+    | 'server'
+    | 'signingUrl'
+    | 'signingUrlHeaders'
+    | 'signingUrlMethod'
+    | 'signingUrlQueryParams'
+    | 'signingUrlWithCredentials'
+    | 'uploadRequestHeaders'> {
+    fileElement?: HTMLInputElement | null;
+    files?: HTMLInputElement['files'] | null;
+    onFinishS3Put?: ReactS3UploaderProps['onFinish'];
+    successResponses?: number[];
+    scrubFilename?: (filename: string) => string;
+  }
+
+  class S3Upload {
+    constructor(options: ReactS3UploaderProps);
+    abortUpload(): void;
+    uploadFile(file: File): Promise<S3Response>;
+    uploadToS3(file: File, signResult: S3Response): void;
+  }
+
+  export default S3Upload;
+}
diff --git a/package-lock.json b/package-lock.json
index 3c0eeec..f1a55a0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,8 +1,23 @@
 {
   "name": "react-s3-uploader",
-  "version": "4.2.0",
+  "version": "4.9.3",
   "lockfileVersion": 1,
+  "requires": true,
   "dependencies": {
+    "@types/prop-types": {
+      "version": "15.7.3",
+      "resolved": "https://registry.npmjs.org/@types/prop-types/-/prop-types-15.7.3.tgz",
+      "integrity": "sha512-KfRL3PuHmqQLOG+2tGpRO26Ctg+Cq1E01D2DMriKEATHgWLfeNDmq9e29Q9WIky0dQ3NPkd1mzYH8Lm936Z9qw=="
+    },
+    "@types/react": {
+      "version": "16.9.19",
+      "resolved": "https://registry.npmjs.org/@types/react/-/react-16.9.19.tgz",
+      "integrity": "sha512-LJV97//H+zqKWMms0kvxaKYJDG05U2TtQB3chRLF8MPNs+MQh/H1aGlyDUxjaHvu08EAGerdX2z4LTBc7ns77A==",
+      "requires": {
+        "@types/prop-types": "*",
+        "csstype": "^2.2.0"
+      }
+    },
     "asap": {
       "version": "2.0.5",
       "resolved": "https://registry.npmjs.org/asap/-/asap-2.0.5.tgz",
@@ -12,6 +27,17 @@
       "version": "2.80.0",
       "resolved": "https://registry.npmjs.org/aws-sdk/-/aws-sdk-2.80.0.tgz",
       "integrity": "sha1-Yc7XR+uYFglIOuxT6NZU08ydFDU=",
+      "requires": {
+        "buffer": "4.9.1",
+        "crypto-browserify": "1.0.9",
+        "jmespath": "0.15.0",
+        "querystring": "0.2.0",
+        "sax": "1.2.1",
+        "url": "0.10.3",
+        "uuid": "3.0.1",
+        "xml2js": "0.4.17",
+        "xmlbuilder": "4.2.1"
+      },
       "dependencies": {
         "uuid": {
           "version": "3.0.1",
@@ -28,7 +54,12 @@
     "buffer": {
       "version": "4.9.1",
       "resolved": "https://registry.npmjs.org/buffer/-/buffer-4.9.1.tgz",
-      "integrity": "sha1-bRu2AbB6TvztlwlBMgkwJ8lbwpg="
+      "integrity": "sha1-bRu2AbB6TvztlwlBMgkwJ8lbwpg=",
+      "requires": {
+        "base64-js": "^1.0.2",
+        "ieee754": "^1.1.4",
+        "isarray": "^1.0.0"
+      }
     },
     "core-js": {
       "version": "1.2.7",
@@ -39,6 +70,11 @@
       "version": "15.6.0",
       "resolved": "https://registry.npmjs.org/create-react-class/-/create-react-class-15.6.0.tgz",
       "integrity": "sha1-q0SEl8JlZuHilBPogyB9V8/nvtQ=",
+      "requires": {
+        "fbjs": "^0.8.9",
+        "loose-envify": "^1.3.1",
+        "object-assign": "^4.1.1"
+      },
       "dependencies": {
         "object-assign": {
           "version": "4.1.1",
@@ -52,15 +88,32 @@
       "resolved": "https://registry.npmjs.org/crypto-browserify/-/crypto-browserify-1.0.9.tgz",
       "integrity": "sha1-zFRJaF37hesRyYKKzHy4erW7/MA="
     },
+    "csstype": {
+      "version": "2.6.8",
+      "resolved": "https://registry.npmjs.org/csstype/-/csstype-2.6.8.tgz",
+      "integrity": "sha512-msVS9qTuMT5zwAGCVm4mxfrZ18BNc6Csd0oJAtiFMZ1FAx1CCvy2+5MDmYoix63LM/6NDbNtodCiGYGmFgO0dA=="
+    },
     "encoding": {
       "version": "0.1.12",
       "resolved": "https://registry.npmjs.org/encoding/-/encoding-0.1.12.tgz",
-      "integrity": "sha1-U4tm8+5izRq1HsMjgp0flIDHS+s="
+      "integrity": "sha1-U4tm8+5izRq1HsMjgp0flIDHS+s=",
+      "requires": {
+        "iconv-lite": "~0.4.13"
+      }
     },
     "fbjs": {
       "version": "0.8.12",
       "resolved": "https://registry.npmjs.org/fbjs/-/fbjs-0.8.12.tgz",
       "integrity": "sha1-ELXZL3bUVXX9Y6IX1OoCvqL47QQ=",
+      "requires": {
+        "core-js": "^1.0.0",
+        "isomorphic-fetch": "^2.1.1",
+        "loose-envify": "^1.0.0",
+        "object-assign": "^4.1.0",
+        "promise": "^7.1.1",
+        "setimmediate": "^1.0.5",
+        "ua-parser-js": "^0.7.9"
+      },
       "dependencies": {
         "object-assign": {
           "version": "4.1.1",
@@ -92,7 +145,11 @@
     "isomorphic-fetch": {
       "version": "2.2.1",
       "resolved": "https://registry.npmjs.org/isomorphic-fetch/-/isomorphic-fetch-2.2.1.tgz",
-      "integrity": "sha1-YRrhrPFPXoH3KVB0coGf6XM1WKk="
+      "integrity": "sha1-YRrhrPFPXoH3KVB0coGf6XM1WKk=",
+      "requires": {
+        "node-fetch": "^1.0.1",
+        "whatwg-fetch": ">=0.10.0"
+      }
     },
     "jmespath": {
       "version": "0.15.0",
@@ -105,19 +162,26 @@
       "integrity": "sha1-mGbfOVECEw449/mWvOtlRDIJwls="
     },
     "lodash": {
-      "version": "4.17.4",
-      "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.4.tgz",
-      "integrity": "sha1-eCA6TRwyiuHYbcpkYONptX9AVa4="
+      "version": "4.17.20",
+      "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.20.tgz",
+      "integrity": "sha512-PlhdFcillOINfeV7Ni6oF1TAEayyZBoZ8bcshTHqOYJYlrqzRK5hagpagky5o4HfCzzd1TRkXPMFq6cKk9rGmA=="
     },
     "loose-envify": {
       "version": "1.3.1",
       "resolved": "https://registry.npmjs.org/loose-envify/-/loose-envify-1.3.1.tgz",
-      "integrity": "sha1-0aitM/qc4OcT1l/dCsi3SNR4yEg="
+      "integrity": "sha1-0aitM/qc4OcT1l/dCsi3SNR4yEg=",
+      "requires": {
+        "js-tokens": "^3.0.0"
+      }
     },
     "node-fetch": {
       "version": "1.7.1",
       "resolved": "https://registry.npmjs.org/node-fetch/-/node-fetch-1.7.1.tgz",
-      "integrity": "sha512-j8XsFGCLw79vWXkZtMSmmLaOk9z5SQ9bV/tkbZVCqvgwzrjAGq66igobLofHtF63NvMTp2WjytpsNTGKa+XRIQ=="
+      "integrity": "sha512-j8XsFGCLw79vWXkZtMSmmLaOk9z5SQ9bV/tkbZVCqvgwzrjAGq66igobLofHtF63NvMTp2WjytpsNTGKa+XRIQ==",
+      "requires": {
+        "encoding": "^0.1.11",
+        "is-stream": "^1.0.1"
+      }
     },
     "object-assign": {
       "version": "2.1.1",
@@ -127,12 +191,19 @@
     "promise": {
       "version": "7.3.1",
       "resolved": "https://registry.npmjs.org/promise/-/promise-7.3.1.tgz",
-      "integrity": "sha512-nolQXZ/4L+bP/UGlkfaIujX9BKxGwmQ9OT4mOt5yvy8iK1h3wqTEJCijzGANTCCl9nWjY41juyAn2K3Q1hLLTg=="
+      "integrity": "sha512-nolQXZ/4L+bP/UGlkfaIujX9BKxGwmQ9OT4mOt5yvy8iK1h3wqTEJCijzGANTCCl9nWjY41juyAn2K3Q1hLLTg==",
+      "requires": {
+        "asap": "~2.0.3"
+      }
     },
     "prop-types": {
       "version": "15.5.10",
       "resolved": "https://registry.npmjs.org/prop-types/-/prop-types-15.5.10.tgz",
-      "integrity": "sha1-J5ffwxJhguOpXj37suiT3ddFYVQ="
+      "integrity": "sha1-J5ffwxJhguOpXj37suiT3ddFYVQ=",
+      "requires": {
+        "fbjs": "^0.8.9",
+        "loose-envify": "^1.3.1"
+      }
     },
     "punycode": {
       "version": "1.3.2",
@@ -154,6 +225,11 @@
       "resolved": "https://registry.npmjs.org/setimmediate/-/setimmediate-1.0.5.tgz",
       "integrity": "sha1-KQy7Iy4waULX1+qbg3Mqt4VvgoU="
     },
+    "typescript": {
+      "version": "3.7.5",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-3.7.5.tgz",
+      "integrity": "sha512-/P5lkRXkWHNAbcJIiHPfRoKqyd7bsyCma1hZNUGfn20qm64T6ZBlrzprymeu918H+mB/0rIg2gGK/BXkhhYgBw=="
+    },
     "ua-parser-js": {
       "version": "0.7.13",
       "resolved": "https://registry.npmjs.org/ua-parser-js/-/ua-parser-js-0.7.13.tgz",
@@ -162,7 +238,11 @@
     "url": {
       "version": "0.10.3",
       "resolved": "https://registry.npmjs.org/url/-/url-0.10.3.tgz",
-      "integrity": "sha1-Ah5NnHcF8hu/N9A861h2dAJ3TGQ="
+      "integrity": "sha1-Ah5NnHcF8hu/N9A861h2dAJ3TGQ=",
+      "requires": {
+        "punycode": "1.3.2",
+        "querystring": "0.2.0"
+      }
     },
     "uuid": {
       "version": "3.1.0",
@@ -177,12 +257,19 @@
     "xml2js": {
       "version": "0.4.17",
       "resolved": "https://registry.npmjs.org/xml2js/-/xml2js-0.4.17.tgz",
-      "integrity": "sha1-F76T6q4/O3eTWceVtBlwWogX6Gg="
+      "integrity": "sha1-F76T6q4/O3eTWceVtBlwWogX6Gg=",
+      "requires": {
+        "sax": ">=0.6.0",
+        "xmlbuilder": "^4.1.0"
+      }
     },
     "xmlbuilder": {
       "version": "4.2.1",
       "resolved": "https://registry.npmjs.org/xmlbuilder/-/xmlbuilder-4.2.1.tgz",
-      "integrity": "sha1-qlijBBoGb5DqoWwvU4n/GfP0YaU="
+      "integrity": "sha1-qlijBBoGb5DqoWwvU4n/GfP0YaU=",
+      "requires": {
+        "lodash": "^4.0.0"
+      }
     }
   }
 }
diff --git a/package.json b/package.json
index 0f89515..6b05543 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "react-s3-uploader",
-  "version": "4.2.0",
+  "version": "4.9.3",
   "description": "React component that renders a file input and automatically uploads to an S3 bucket",
   "main": "index.js",
   "scripts": {
@@ -10,6 +10,7 @@
     "type": "git",
     "url": "git@github.com:odysseyscience/react-s3-uploader.git"
   },
+  "types": "index.d.ts",
   "keywords": [
     "react",
     "upload",
@@ -24,14 +25,17 @@
   },
   "homepage": "https://github.com/odysseyscience/react-s3-uploader",
   "dependencies": {
-    "aws-sdk": "2.x",
     "create-react-class": "^15.5.2",
+    "mime-types": "^2.1.24",
     "object-assign": "^2.0.0",
     "prop-types": "^15.5.8",
     "uuid": "^3.1.0"
   },
-  "peerDependencies": {
-    "react": "*",
-    "react-dom": "*"
+  "devDependencies": {
+    "@types/react": "*",
+    "typescript": "^3.7.5"
+  },
+  "optionalDependencies": {
+    "aws-sdk": "2.x"
   }
 }
diff --git a/s3router.js b/s3router.js
index 96faa23..65f28f9 100644
--- a/s3router.js
+++ b/s3router.js
@@ -10,7 +10,11 @@ function checkTrailingSlash(path) {
     return path;
 }
 
-function S3Router(options) {
+function S3Router(options, middleware) {
+
+    if (!middleware) {
+        middleware = [];
+    }
 
     var S3_BUCKET = options.bucket,
         getFileKeyDir = options.getFileKeyDir || function() { return ""; };
@@ -19,13 +23,21 @@ function S3Router(options) {
         throw new Error("S3_BUCKET is required.");
     }
 
-    var s3Options = {};
-    if (options.region) {
-      s3Options.region = options.region;
-    }
-    if (options.signatureVersion) {
+    var getS3 = options.getS3;
+    if (!getS3) {
+      var s3Options = {};
+      if (options.region) {
+        s3Options.region = options.region;
+      }
+      if (options.signatureVersion) {
         s3Options.signatureVersion = options.signatureVersion;
+      }
+
+      getS3 = function() {
+        return new aws.S3(s3Options);
+      };
     }
+
     if (options.uniquePrefix === undefined) {
         options.uniquePrefix = true;
     }
@@ -41,7 +53,7 @@ function S3Router(options) {
             Bucket: S3_BUCKET,
             Key: checkTrailingSlash(getFileKeyDir(req)) + req.params[0]
         };
-        var s3 = new aws.S3(s3Options);
+        var s3 = getS3();
         s3.getSignedUrl('getObject', params, function(err, url) {
             res.redirect(url);
         });
@@ -50,14 +62,14 @@ function S3Router(options) {
     /**
      * Image specific route.
      */
-    router.get(/\/img\/(.*)/, function(req, res) {
+    router.get(/\/img\/(.*)/, middleware, function(req, res) {
         return tempRedirect(req, res);
     });
 
     /**
      * Other file type(s) route.
      */
-    router.get(/\/uploads\/(.*)/, function(req, res) {
+    router.get(/\/uploads\/(.*)/, middleware, function(req, res) {
         return tempRedirect(req, res);
     });
 
@@ -65,8 +77,8 @@ function S3Router(options) {
      * Returns an object with `signedUrl` and `publicUrl` properties that
      * give temporary access to PUT an object in an S3 bucket.
      */
-    router.get('/sign', function(req, res) {
-        var filename = (options.uniquePrefix ? uuidv4() + "_" : "") + req.query.objectName;
+    router.get('/sign', middleware, function(req, res) {
+        var filename = (req.query.path || '') + (options.uniquePrefix ? uuidv4() + "_" : "") + req.query.objectName;
         var mimeType = req.query.contentType;
         var fileKey = checkTrailingSlash(getFileKeyDir(req)) + filename;
         // Set any custom headers
@@ -74,11 +86,11 @@ function S3Router(options) {
           res.set(options.headers);
         }
 
-        var s3 = new aws.S3(s3Options);
+        var s3 = getS3();
         var params = {
             Bucket: S3_BUCKET,
             Key: fileKey,
-            Expires: 60,
+            Expires: options.signatureExpires || 60,
             ContentType: mimeType,
             ACL: options.ACL || 'private'
         };
diff --git a/s3upload.js b/s3upload.js
index 988b3db..7a30cb4 100644
--- a/s3upload.js
+++ b/s3upload.js
@@ -3,9 +3,12 @@
  * https://github.com/flyingsparx/NodeDirectUploader
  */
 
+var mime = require('mime-types');
+
 S3Upload.prototype.server = '';
 S3Upload.prototype.signingUrl = '/sign-s3';
 S3Upload.prototype.signingUrlMethod = 'GET';
+S3Upload.prototype.successResponses = [200, 201];
 S3Upload.prototype.fileElement = null;
 S3Upload.prototype.files = null;
 
@@ -26,6 +29,8 @@ S3Upload.prototype.onError = function(status, file) {
     return console.log('base.onError()', status);
 };
 
+S3Upload.prototype.onSignedUrl = function(result) {};
+
 S3Upload.prototype.scrubFilename = function(filename) {
     return filename.replace(/[^\w\d_\-\.]+/ig, '');
 };
@@ -43,14 +48,18 @@ function S3Upload(options) {
     this.handleFileSelect(files);
 }
 
+function getFileMimeType(file) {
+    return file.type || mime.lookup(file.name);
+}
+
 S3Upload.prototype.handleFileSelect = function(files) {
     var result = [];
     for (var i=0; i < files.length; i++) {
         var file = files[i];
         this.preprocess(file, function(processedFile){
-          this.onProgress(0, 'Waiting', processedFile);
-          result.push(this.uploadFile(processedFile));
-          return result;
+            this.onProgress(0, 'Waiting', processedFile);
+            result.push(this.uploadFile(processedFile));
+            return result;
         }.bind(this));
     }
 };
@@ -75,9 +84,21 @@ S3Upload.prototype.createCORSRequest = function(method, url, opts) {
     return xhr;
 };
 
+S3Upload.prototype._getErrorRequestContext = function (xhr) {
+    return {
+        response: xhr.responseText,
+        status: xhr.status,
+        statusText: xhr.statusText,
+        readyState: xhr.readyState
+    };
+}
+
 S3Upload.prototype.executeOnSignedUrl = function(file, callback) {
     var fileName = this.scrubFilename(file.name);
-    var queryString = '?objectName=' + fileName + '&contentType=' + encodeURIComponent(file.type);
+    var queryString = '?objectName=' + fileName + '&contentType=' + encodeURIComponent(getFileMimeType(file));
+    if (this.s3path) {
+        queryString += '&path=' + encodeURIComponent(this.s3path);
+    }
     if (this.signingUrlQueryParams) {
         var signingUrlQueryParams = typeof this.signingUrlQueryParams === 'function' ? this.signingUrlQueryParams() : this.signingUrlQueryParams;
         Object.keys(signingUrlQueryParams).forEach(function(key) {
@@ -86,7 +107,7 @@ S3Upload.prototype.executeOnSignedUrl = function(file, callback) {
         });
     }
     var xhr = this.createCORSRequest(this.signingUrlMethod,
-        this.server + this.signingUrl + queryString, { withCredentials: this.signingUrlWithCredentials });
+      this.server + this.signingUrl + queryString, { withCredentials: this.signingUrlWithCredentials });
     if (this.signingUrlHeaders) {
         var signingUrlHeaders = typeof this.signingUrlHeaders === 'function' ? this.signingUrlHeaders() : this.signingUrlHeaders;
         Object.keys(signingUrlHeaders).forEach(function(key) {
@@ -96,17 +117,26 @@ S3Upload.prototype.executeOnSignedUrl = function(file, callback) {
     }
     xhr.overrideMimeType && xhr.overrideMimeType('text/plain; charset=x-user-defined');
     xhr.onreadystatechange = function() {
-        if (xhr.readyState === 4 && xhr.status === 200) {
+        if (xhr.readyState === 4 && this.successResponses.indexOf(xhr.status) >= 0) {
             var result;
             try {
                 result = JSON.parse(xhr.responseText);
+                this.onSignedUrl( result );
             } catch (error) {
-                this.onError('Invalid response from server', file);
+                this.onError(
+                  'Invalid response from server',
+                  file,
+                  this._getErrorRequestContext(xhr)
+                );
                 return false;
             }
             return callback(result);
-        } else if (xhr.readyState === 4 && xhr.status !== 200) {
-            return this.onError('Could not contact request signing server. Status = ' + xhr.status, file);
+        } else if (xhr.readyState === 4 && this.successResponses.indexOf(xhr.status) < 0) {
+            return this.onError(
+              'Could not contact request signing server. Status = ' + xhr.status,
+              file,
+              this._getErrorRequestContext(xhr)
+            );
         }
     }.bind(this);
     return xhr.send();
@@ -115,18 +145,26 @@ S3Upload.prototype.executeOnSignedUrl = function(file, callback) {
 S3Upload.prototype.uploadToS3 = function(file, signResult) {
     var xhr = this.createCORSRequest('PUT', signResult.signedUrl);
     if (!xhr) {
-        this.onError('CORS not supported', file);
+        this.onError('CORS not supported', file, {});
     } else {
         xhr.onload = function() {
-            if (xhr.status === 200) {
+            if (this.successResponses.indexOf(xhr.status) >= 0) {
                 this.onProgress(100, 'Upload completed', file);
                 return this.onFinishS3Put(signResult, file);
             } else {
-                return this.onError('Upload error: ' + xhr.status, file);
+                return this.onError(
+                  'Upload error: ' + xhr.status,
+                  file,
+                  this._getErrorRequestContext(xhr)
+                );
             }
         }.bind(this);
         xhr.onerror = function() {
-            return this.onError('XHR error', file);
+            return this.onError(
+              'XHR error',
+              file,
+              this._getErrorRequestContext(xhr)
+            );
         }.bind(this);
         xhr.upload.onprogress = function(e) {
             var percentLoaded;
@@ -136,11 +174,16 @@ S3Upload.prototype.uploadToS3 = function(file, signResult) {
             }
         }.bind(this);
     }
-    xhr.setRequestHeader('Content-Type', file.type);
+
+    var fileType = getFileMimeType(file);
+    var headers = {
+      'content-type': fileType
+    };
+
     if (this.contentDisposition) {
         var disposition = this.contentDisposition;
         if (disposition === 'auto') {
-            if (file.type.substr(0, 6) === 'image/') {
+            if (fileType.substr(0, 6) === 'image/') {
                 disposition = 'inline';
             } else {
                 disposition = 'attachment';
@@ -148,24 +191,19 @@ S3Upload.prototype.uploadToS3 = function(file, signResult) {
         }
 
         var fileName = this.scrubFilename(file.name)
-        xhr.setRequestHeader('Content-Disposition', disposition + '; filename="' + fileName + '"');
-    }
-    if (signResult.headers) {
-        var signResultHeaders = signResult.headers
-        Object.keys(signResultHeaders).forEach(function(key) {
-            var val = signResultHeaders[key];
-            xhr.setRequestHeader(key, val);
-        })
+        headers['content-disposition'] = disposition + '; filename="' + fileName + '"';
     }
-    if (this.uploadRequestHeaders) {
-        var uploadRequestHeaders = this.uploadRequestHeaders;
-        Object.keys(uploadRequestHeaders).forEach(function(key) {
-            var val = uploadRequestHeaders[key];
-            xhr.setRequestHeader(key, val);
-        });
-    } else {
+    if (!this.uploadRequestHeaders) {
         xhr.setRequestHeader('x-amz-acl', 'public-read');
     }
+    [signResult.headers, this.uploadRequestHeaders].filter(Boolean).forEach(function (hdrs) {
+        Object.entries(hdrs).forEach(function(pair) {
+            headers[pair[0].toLowerCase()] = pair[1];
+        })
+    });
+    Object.entries(headers).forEach(function (pair) {
+        xhr.setRequestHeader(pair[0], pair[1]);
+    })
     this.httprequest = xhr;
     return xhr.send(file);
 };
diff --git a/yarn.lock b/yarn.lock
new file mode 100644
index 0000000..06d9048
--- /dev/null
+++ b/yarn.lock
@@ -0,0 +1,187 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+"@types/prop-types@*":
+  version "15.7.3"
+  resolved "https://registry.yarnpkg.com/@types/prop-types/-/prop-types-15.7.3.tgz#2ab0d5da2e5815f94b0b9d4b95d1e5f243ab2ca7"
+  integrity sha512-KfRL3PuHmqQLOG+2tGpRO26Ctg+Cq1E01D2DMriKEATHgWLfeNDmq9e29Q9WIky0dQ3NPkd1mzYH8Lm936Z9qw==
+
+"@types/react@*":
+  version "16.9.55"
+  resolved "https://registry.yarnpkg.com/@types/react/-/react-16.9.55.tgz#47078587f5bfe028a23b6b46c7b94ac0d436acff"
+  integrity sha512-6KLe6lkILeRwyyy7yG9rULKJ0sXplUsl98MGoCfpteXf9sPWFWWMknDcsvubcpaTdBuxtsLF6HDUwdApZL/xIg==
+  dependencies:
+    "@types/prop-types" "*"
+    csstype "^3.0.2"
+
+aws-sdk@2.x:
+  version "2.784.0"
+  resolved "https://registry.yarnpkg.com/aws-sdk/-/aws-sdk-2.784.0.tgz#70136a537d5c977a9e9a2e8b6a234b45ec2da0a1"
+  integrity sha512-+KBkqH7t/XE91Fqn8eyJeNIWsnhSWL8bSUqFD7TfE3FN07MTlC0nprGYp+2WfcYNz5i8Bus1vY2DHNVhtTImnw==
+  dependencies:
+    buffer "4.9.2"
+    events "1.1.1"
+    ieee754 "1.1.13"
+    jmespath "0.15.0"
+    querystring "0.2.0"
+    sax "1.2.1"
+    url "0.10.3"
+    uuid "3.3.2"
+    xml2js "0.4.19"
+
+base64-js@^1.0.2:
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/base64-js/-/base64-js-1.3.1.tgz#58ece8cb75dd07e71ed08c736abc5fac4dbf8df1"
+  integrity sha512-mLQ4i2QO1ytvGWFWmcngKO//JXAQueZvwEKtjgQFM4jIK0kU+ytMfplL8j+n5mspOfjHwoAg+9yhb7BwAHm36g==
+
+buffer@4.9.2:
+  version "4.9.2"
+  resolved "https://registry.yarnpkg.com/buffer/-/buffer-4.9.2.tgz#230ead344002988644841ab0244af8c44bbe3ef8"
+  integrity sha512-xq+q3SRMOxGivLhBNaUdC64hDTQwejJ+H0T/NB1XMtTVEwNTrfFF3gAxiyW0Bu/xWEGhjVKgUcMhCrUy2+uCWg==
+  dependencies:
+    base64-js "^1.0.2"
+    ieee754 "^1.1.4"
+    isarray "^1.0.0"
+
+create-react-class@^15.5.2:
+  version "15.7.0"
+  resolved "https://registry.yarnpkg.com/create-react-class/-/create-react-class-15.7.0.tgz#7499d7ca2e69bb51d13faf59bd04f0c65a1d6c1e"
+  integrity sha512-QZv4sFWG9S5RUvkTYWbflxeZX+JG7Cz0Tn33rQBJ+WFQTqTfUTjMjiv9tnfXazjsO5r0KhPs+AqCjyrQX6h2ng==
+  dependencies:
+    loose-envify "^1.3.1"
+    object-assign "^4.1.1"
+
+csstype@^3.0.2:
+  version "3.0.4"
+  resolved "https://registry.yarnpkg.com/csstype/-/csstype-3.0.4.tgz#b156d7be03b84ff425c9a0a4b1e5f4da9c5ca888"
+  integrity sha512-xc8DUsCLmjvCfoD7LTGE0ou2MIWLx0K9RCZwSHMOdynqRsP4MtUcLeqh1HcQ2dInwDTqn+3CE0/FZh1et+p4jA==
+
+events@1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/events/-/events-1.1.1.tgz#9ebdb7635ad099c70dcc4c2a1f5004288e8bd924"
+  integrity sha1-nr23Y1rQmccNzEwqH1AEKI6L2SQ=
+
+ieee754@1.1.13:
+  version "1.1.13"
+  resolved "https://registry.yarnpkg.com/ieee754/-/ieee754-1.1.13.tgz#ec168558e95aa181fd87d37f55c32bbcb6708b84"
+  integrity sha512-4vf7I2LYV/HaWerSo3XmlMkp5eZ83i+/CDluXi/IGTs/O1sejBNhTtnxzmRZfvOUqj7lZjqHkeTvpgSFDlWZTg==
+
+ieee754@^1.1.4:
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/ieee754/-/ieee754-1.2.1.tgz#8eb7a10a63fff25d15a57b001586d177d1b0d352"
+  integrity sha512-dcyqhDvX1C46lXZcVqCpK+FtMRQVdIMN6/Df5js2zouUsqG7I6sFxitIC+7KYK29KdXOLHdu9zL4sFnoVQnqaA==
+
+isarray@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/isarray/-/isarray-1.0.0.tgz#bb935d48582cba168c06834957a54a3e07124f11"
+  integrity sha1-u5NdSFgsuhaMBoNJV6VKPgcSTxE=
+
+jmespath@0.15.0:
+  version "0.15.0"
+  resolved "https://registry.yarnpkg.com/jmespath/-/jmespath-0.15.0.tgz#a3f222a9aae9f966f5d27c796510e28091764217"
+  integrity sha1-o/Iiqarp+Wb10nx5ZRDigJF2Qhc=
+
+"js-tokens@^3.0.0 || ^4.0.0":
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-4.0.0.tgz#19203fb59991df98e3a287050d4647cdeaf32499"
+  integrity sha512-RdJUflcE3cUzKiMqQgsCu06FPu9UdIJO0beYbPhHN4k6apgJtifcoCtT9bcxOpYBtpD2kCM6Sbzg4CausW/PKQ==
+
+loose-envify@^1.3.1, loose-envify@^1.4.0:
+  version "1.4.0"
+  resolved "https://registry.yarnpkg.com/loose-envify/-/loose-envify-1.4.0.tgz#71ee51fa7be4caec1a63839f7e682d8132d30caf"
+  integrity sha512-lyuxPGr/Wfhrlem2CL/UcnUc1zcqKAImBDzukY7Y5F/yQiNdko6+fRLevlw1HgMySw7f611UIY408EtxRSoK3Q==
+  dependencies:
+    js-tokens "^3.0.0 || ^4.0.0"
+
+mime-db@1.44.0:
+  version "1.44.0"
+  resolved "https://registry.yarnpkg.com/mime-db/-/mime-db-1.44.0.tgz#fa11c5eb0aca1334b4233cb4d52f10c5a6272f92"
+  integrity sha512-/NOTfLrsPBVeH7YtFPgsVWveuL+4SjjYxaQ1xtM1KMFj7HdxlBlxeyNLzhyJVx7r4rZGJAZ/6lkKCitSc/Nmpg==
+
+mime-types@^2.1.24:
+  version "2.1.27"
+  resolved "https://registry.yarnpkg.com/mime-types/-/mime-types-2.1.27.tgz#47949f98e279ea53119f5722e0f34e529bec009f"
+  integrity sha512-JIhqnCasI9yD+SsmkquHBxTSEuZdQX5BuQnS2Vc7puQQQ+8yiP5AY5uWhpdv4YL4VM5c6iliiYWPgJ/nJQLp7w==
+  dependencies:
+    mime-db "1.44.0"
+
+object-assign@^2.0.0:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/object-assign/-/object-assign-2.1.1.tgz#43c36e5d569ff8e4816c4efa8be02d26967c18aa"
+  integrity sha1-Q8NuXVaf+OSBbE76i+AtJpZ8GKo=
+
+object-assign@^4.1.1:
+  version "4.1.1"
+  resolved "https://registry.yarnpkg.com/object-assign/-/object-assign-4.1.1.tgz#2109adc7965887cfc05cbbd442cac8bfbb360863"
+  integrity sha1-IQmtx5ZYh8/AXLvUQsrIv7s2CGM=
+
+prop-types@^15.5.8:
+  version "15.7.2"
+  resolved "https://registry.yarnpkg.com/prop-types/-/prop-types-15.7.2.tgz#52c41e75b8c87e72b9d9360e0206b99dcbffa6c5"
+  integrity sha512-8QQikdH7//R2vurIJSutZ1smHYTcLpRWEOlHnzcWHmBYrOGUysKwSsrC89BCiFj3CbrfJ/nXFdJepOVrY1GCHQ==
+  dependencies:
+    loose-envify "^1.4.0"
+    object-assign "^4.1.1"
+    react-is "^16.8.1"
+
+punycode@1.3.2:
+  version "1.3.2"
+  resolved "https://registry.yarnpkg.com/punycode/-/punycode-1.3.2.tgz#9653a036fb7c1ee42342f2325cceefea3926c48d"
+  integrity sha1-llOgNvt8HuQjQvIyXM7v6jkmxI0=
+
+querystring@0.2.0:
+  version "0.2.0"
+  resolved "https://registry.yarnpkg.com/querystring/-/querystring-0.2.0.tgz#b209849203bb25df820da756e747005878521620"
+  integrity sha1-sgmEkgO7Jd+CDadW50cAWHhSFiA=
+
+react-is@^16.8.1:
+  version "16.13.1"
+  resolved "https://registry.yarnpkg.com/react-is/-/react-is-16.13.1.tgz#789729a4dc36de2999dc156dd6c1d9c18cea56a4"
+  integrity sha512-24e6ynE2H+OKt4kqsOvNd8kBpV65zoxbA4BVsEOB3ARVWQki/DHzaUoC5KuON/BiccDaCCTZBuOcfZs70kR8bQ==
+
+sax@1.2.1:
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/sax/-/sax-1.2.1.tgz#7b8e656190b228e81a66aea748480d828cd2d37a"
+  integrity sha1-e45lYZCyKOgaZq6nSEgNgozS03o=
+
+sax@>=0.6.0:
+  version "1.2.4"
+  resolved "https://registry.yarnpkg.com/sax/-/sax-1.2.4.tgz#2816234e2378bddc4e5354fab5caa895df7100d9"
+  integrity sha512-NqVDv9TpANUjFm0N8uM5GxL36UgKi9/atZw+x7YFnQ8ckwFGKrl4xX4yWtrey3UJm5nP1kUbnYgLopqWNSRhWw==
+
+typescript@^3.7.5:
+  version "3.9.7"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.9.7.tgz#98d600a5ebdc38f40cb277522f12dc800e9e25fa"
+  integrity sha512-BLbiRkiBzAwsjut4x/dsibSTB6yWpwT5qWmC2OfuCg3GgVQCSgMs4vEctYPhsaGtd0AeuuHMkjZ2h2WG8MSzRw==
+
+url@0.10.3:
+  version "0.10.3"
+  resolved "https://registry.yarnpkg.com/url/-/url-0.10.3.tgz#021e4d9c7705f21bbf37d03ceb58767402774c64"
+  integrity sha1-Ah5NnHcF8hu/N9A861h2dAJ3TGQ=
+  dependencies:
+    punycode "1.3.2"
+    querystring "0.2.0"
+
+uuid@3.3.2:
+  version "3.3.2"
+  resolved "https://registry.yarnpkg.com/uuid/-/uuid-3.3.2.tgz#1b4af4955eb3077c501c23872fc6513811587131"
+  integrity sha512-yXJmeNaw3DnnKAOKJE51sL/ZaYfWJRl1pK9dr19YFCu0ObS231AB1/LbqTKRAQ5kw8A90rA6fr4riOUpTZvQZA==
+
+uuid@^3.1.0:
+  version "3.4.0"
+  resolved "https://registry.yarnpkg.com/uuid/-/uuid-3.4.0.tgz#b23e4358afa8a202fe7a100af1f5f883f02007ee"
+  integrity sha512-HjSDRw6gZE5JMggctHBcjVak08+KEVhSIiDzFnT9S9aegmp85S/bReBVTb4QTFaRNptJ9kuYaNhnbNEOkbKb/A==
+
+xml2js@0.4.19:
+  version "0.4.19"
+  resolved "https://registry.yarnpkg.com/xml2js/-/xml2js-0.4.19.tgz#686c20f213209e94abf0d1bcf1efaa291c7827a7"
+  integrity sha512-esZnJZJOiJR9wWKMyuvSE1y6Dq5LCuJanqhxslH2bxM6duahNZ+HMpCLhBQGZkbX6xRf8x1Y2eJlgt2q3qo49Q==
+  dependencies:
+    sax ">=0.6.0"
+    xmlbuilder "~9.0.1"
+
+xmlbuilder@~9.0.1:
+  version "9.0.7"
+  resolved "https://registry.yarnpkg.com/xmlbuilder/-/xmlbuilder-9.0.7.tgz#132ee63d2ec5565c557e20f4c22df9aca686b10d"
+  integrity sha1-Ey7mPS7FVlxVfiD0wi35rKaGsQ0=