A10Wu2cF

1var crypto = require('crypto');
2
3// This is the entry function that produces data for the frontend
4// config is hash of S3 configuration:
5// * bucket
6// * region
7// * accessKey
8// * secretKey
9function s3Credentials(config, params) {
10  return {
11    endpoint_url: "https://" + config.bucket + ".s3.amazonaws.com",
12    params: s3Params(config, params)
13  }
14}
15
16// Returns the parameters that must be passed to the API call
17function s3Params(config, params) {
18  var credential = amzCredential(config);
19  var policy = s3UploadPolicy(config, params, credential);
20  var policyBase64 = new Buffer(JSON.stringify(policy)).toString('base64');
21  return {
22    key: params.filename,
23    acl: 'public-read',
24    success_action_status: '201',
25    policy: policyBase64,
26    "content-type": params.contentType,
27    'x-amz-algorithm': 'AWS4-HMAC-SHA256',
28    'x-amz-credential': credential,
29    'x-amz-date': dateString() + 'T000000Z',
30    'x-amz-signature': s3UploadSignature(config, policyBase64, credential)
31  }
32}
33
34function dateString() {
35  var date = new Date().toISOString();
36  return date.substr(0, 4) + date.substr(5, 2) + date.substr(8, 2);
37}
38
39function amzCredential(config) {
40  return [config.accessKey, dateString(), config.region, 's3/aws4_request'].join('/')
41}
42
43// Constructs the policy
44function s3UploadPolicy(config, params, credential) {
45  return {
46    // 5 minutes into the future
47    expiration: new Date((new Date).getTime() + (5 * 60 * 1000)).toISOString(),
48    conditions: [
49      { bucket: config.bucket },
50      { key: params.filename },
51      { acl: 'public-read' },
52      { success_action_status: "201" },
53      // Optionally control content type and file size
54      // A content-type clause is required (even if it's all-permissive)
55      // so that the uploader can specify a content-type for the file
56      ['starts-with', '$Content-Type',  ''],
57      ['content-length-range', 0, 100000],
58      { 'x-amz-algorithm': 'AWS4-HMAC-SHA256' },
59      { 'x-amz-credential': credential },
60      { 'x-amz-date': dateString() + 'T000000Z' }
61    ],
62  }
63}
64
65function hmac(key, string) {
66  var hmac = require('crypto').createHmac('sha256', key);
67  hmac.end(string);
68  return hmac.read();
69}
70
71// Signs the policy with the credential
72function s3UploadSignature(config, policyBase64, credential) {
73  var dateKey = hmac('AWS4' + config.secretKey, dateString());
74  var dateRegionKey = hmac(dateKey, config.region);
75  var dateRegionServiceKey = hmac(dateRegionKey, 's3');
76  var signingKey = hmac(dateRegionServiceKey, 'aws4_request');
77  return hmac(signingKey, policyBase64).toString('hex');
78}
79
80module.exports = {
81  s3Credentials: s3Credentials
82}
83	
84// Requires jQuery and blueimp's jQuery.fileUpload
85var bucket = 'my-trybucket';
86// client-side validation by fileUpload should match the policy
87// restrictions so that the checks fail early
88var acceptFileType = /.*/i;
89var maxFileSizee = 10000;
90// The URL to your endpoint that maps to s3Credentials function
91var credentialsUrl = '/s3_credentials';
92// The URL to your endpoint to register the uploaded file
93var uploadUrl = '/upload';
94
95window.initS3FileUpload = function($fileInput) {
96    console.log($fileInput);
97  $fileInput.fileupload({
98    // acceptFileTypes: acceptFileType,
99    maxFileSize: maxFileSizee,
100    url: 'https://' + bucket + '.s3.amazonaws.com',
101    paramName: 'file',
102    add: s3add,
103    dataType: 'xml',
104    done: onS3Done
105  });
106};
107
108// This function retrieves s3 parameters from our server API and appends them
109// to the upload form.
110function s3add(e, data) {
111  var filename = data.files[0].name;
112  var contentType = data.files[0].type;
113  console.log("File Name is:"+filename);
114  console.log("File Name is:"+contentType);
115  var params = [];
116  $.ajax({
117    url: credentialsUrl,
118    type: 'GET',
119    dataType: 'json',
120    data: {
121      filename: filename,
122      content_type: contentType
123    },
124    success: function(s3Data) {
125      data.url = s3Data.endpoint_url;
126      data.formData = s3Data.params;
127      data.submit();
128    }
129  });
130  return params;
131};
132
133function onS3Done(e, data) {
134  var s3Url = $(data.jqXHR.responseXML).find('Location').text();
135  var s3Key = $(data.jqXHR.responseXML).find('Key').text();
136  // Typically, after uploading a file to S3, you want to register that file with
137  // your backend. Remember that we did not persist anything before the upload.
138  console.log($('<a/>').attr('href', s3Url).text('File uploaded at '+s3Url).appendTo($('body')));
139};