1. Create a presigned URL
1.1. 描述
预签名url创建一个临时链接，可用于公开共享对象，或提供一个临时目标,而不需要提供身份验证信息。
创建预签名url最简单的方法是使用AWS CLI:
$ aws --endpoint-url=https://{endpoint} s3 presign s3://bucket-1/new-file
也可以设置URL的过期时间(以秒为单位)(默认为3600):
$ aws --endpoint-url=https://{endpoint} s3 presign s3://bucket-1/new-file --expires-in 600
1.2. 下面是一个示例预签名URL
https://cn-east-1.cloud-oss.com/examplebucket/test.txt
?X-Amz-Algorithm=AWS4-HMAC-SHA256
&X-Amz-Credential=<your-access-key-id>/20180721/cn-east-1/s3/aws4_request
&X-Amz-Date=20180721T201207Z
&X-Amz-Expires=86400
&X-Amz-SignedHeaders=host
&X-Amz-Signature=<signature-value>
1.3. 创建预签名URL以下载对象
Java Example
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.time.format.DateTimeFormatter;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.util.Formatter;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
public class CoSHMAC {
// constants
private static final String accessKey = "{COS_HMAC_ACCESS_KEY_ID}";
private static final String secretKey = "{COS_HMAC_SECRET_ACCESS_KEY}";
private static final String httpMethod = "GET";
private static final String host = "{endpoint}";
private static final String region = "";
private static final String endpoint = "https://" + host;
private static final String bucket = "example-bucket";
private static final String objectKey = "example-object";
private static final String requestParameters = "";
private static final int expiration = 86400; // time in seconds
public static void main(String[] args) {
try {
// assemble the standardized request
ZonedDateTime time = ZonedDateTime.now(ZoneOffset.UTC);
String datestamp = time.format(DateTimeFormatter.ofPattern("yyyyMMdd"));
String timestamp = datestamp + "T" + time.format(DateTimeFormatter.ofPattern("HHmmss")) + "Z";
String standardizedQuerystring = "X-Amz-Algorithm=AWS4-HMAC-SHA256" +
"&X-Amz-Credential=" + URLEncoder.encode(accessKey + "/" + datestamp + "/" + region + "/s3/aws4_request", StandardCharsets.UTF_8.toString()) +
"&X-Amz-Date=" + timestamp +
"&X-Amz-Expires=" + String.valueOf(expiration) +
"&X-Amz-SignedHeaders=host";
String standardizedResource = "/" + bucket + "/" + objectKey;
String payloadHash = "UNSIGNED-PAYLOAD";
String standardizedHeaders = "host:" + host;
String signedHeaders = "host";
String standardizedRequest = httpMethod + "\n" +
standardizedResource + "\n" +
standardizedQuerystring + "\n" +
standardizedHeaders + "\n" +
"\n" +
signedHeaders + "\n" +
payloadHash;
// assemble string-to-sign
String hashingAlgorithm = "AWS4-HMAC-SHA256";
String credentialScope = datestamp + "/" + region + "/" + "s3" + "/" + "aws4_request";
String sts = hashingAlgorithm + "\n" +
timestamp + "\n" +
credentialScope + "\n" +
hashHex(standardizedRequest);
// generate the signature
byte[] signatureKey = createSignatureKey(secretKey, datestamp, region, "s3");
String signature = hmacHex(signatureKey, sts);
// create and send the request
String requestUrl = endpoint + "/" +
bucket + "/" +
objectKey + "?" +
standardizedQuerystring +
"&X-Amz-Signature=" +
signature;
URL urlObj = new URL(requestUrl);
HttpURLConnection con = (HttpURLConnection) urlObj.openConnection();
con.setRequestMethod(httpMethod);
System.out.printf("\nSending %s request to IBM COS -----------------------", httpMethod);
System.out.println("Request URL = " + requestUrl);
int responseCode = con.getResponseCode();
System.out.println("\nResponse from IBM COS ----------------------------------");
System.out.printf("Response code: %d\n\n", responseCode);
BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
//print result
System.out.println(response.toString());
con.disconnect();
// this information can be helpful in troubleshooting, or to better
// understand what goes into signature creation
System.out.println("These are the values used to construct this request.");
System.out.println("Request details -----------------------------------------");
System.out.printf("http_method: %s\n", httpMethod);
System.out.printf("host: %s\n", host);
System.out.printf("region: %s\n", region);
System.out.printf("endpoint: %s\n", endpoint);
System.out.printf("bucket: %s\n", bucket);
System.out.printf("object_key: %s\n", objectKey);
System.out.printf("timestamp: %s\n", timestamp);
System.out.printf("datestamp: %s\n", datestamp);
System.out.println("Standardized request details ----------------------------");
System.out.printf("standardized_resource: %s\n", standardizedResource);
System.out.printf("standardized_querystring: %s\n", standardizedQuerystring);
System.out.printf("standardized_headers: %s\n", standardizedHeaders);
System.out.printf("signed_headers: %s\n", signedHeaders);
System.out.printf("payload_hash: %s\n", payloadHash);
System.out.printf("standardized_request: %s\n", standardizedRequest);
System.out.println("String-to-sign details ----------------------------------");
System.out.printf("credential_scope: %s\n", credentialScope);
System.out.printf("string-to-sign: %s\n", sts);
System.out.printf("signature_key: %s\n", signatureKey);
System.out.printf("signature: %s\n", signature);
System.out.println("Because the signature key has non-ASCII characters, it is");
System.out.println("necessary to create a hexadecimal digest for the purposes");
System.out.println("of checking against this example.");
String signatureKeyHex = createHexSignatureKey(secretKey, datestamp, region, "s3");
System.out.printf("signature_key (hexidecimal): %s\n", signatureKeyHex);
System.out.println("Header details ------------------------------------------");
System.out.printf("pre-signed url: %s\n", requestUrl);
}
catch (Exception ex) {
System.out.printf("Error: %s\n", ex.getMessage());
}
}
private static String toHexString(byte[] bytes) {
Formatter formatter = new Formatter();
for (byte b : bytes) {
formatter.format("%02x", b);
}
return formatter.toString();
}
public static byte[] hash(byte[] key, String msg) {
byte[] returnVal = null;
try {
SecretKeySpec signingKey = new SecretKeySpec(key, "HmacSHA256");
Mac mac = Mac.getInstance("HmacSHA256");
mac.init(signingKey);
returnVal = mac.doFinal(msg.getBytes("UTF8"));
}
catch (Exception ex) {
throw ex;
}
finally {
return returnVal;
}
}
public static String hmacHex(byte[] key, String msg) {
String returnVal = null;
try {
returnVal = toHexString(hash(key, msg));
}
catch (Exception ex) {
}
finally {
return returnVal;
}
}
public static String hashHex(String msg) {
String returnVal = null;
try {
MessageDigest digest = MessageDigest.getInstance("SHA-256");
byte[] encodedhash = digest.digest(msg.getBytes(StandardCharsets.UTF_8));
returnVal = toHexString(encodedhash);
}
catch (Exception ex) {
throw ex;
}
finally {
return returnVal;
}
}
// region is a wildcard value that takes the place of the AWS region value
// as COS doesn"t use the same conventions for regions, this parameter can accept any string
public static byte[] createSignatureKey(String key, String datestamp, String region, String service) {
byte[] returnVal = null;
try {
byte[] keyDate = hash(("AWS4" + key).getBytes("UTF8"), datestamp);
byte[] keyString = hash(keyDate, region);
byte[] keyService = hash(keyString, service);
byte[] keySigning = hash(keyService, "aws4_request");
returnVal = keySigning;
}
catch (Exception ex) {
throw ex;
}
finally {
return returnVal;
}
}
public static String createHexSignatureKey(String key, String datestamp, String region, String service) {
String returnVal = null;
try {
returnVal = toHexString(createSignatureKey(key, datestamp, region, service));
}
catch (Exception ex) {
throw ex;
}
finally {
return returnVal;
}
}
}
Create a presigned URL to upload an object
import datetime
import hashlib
import hmac
import requests
from requests.utils import quote
access_key = '{COS_HMAC_ACCESS_KEY_ID}'
secret_key = '{COS_HMAC_SECRET_ACCESS_KEY}'
# request elements
http_method = 'PUT'
region = ''
bucket = 'example-bucket'
cos_endpoint = '{endpoint}'
host = cos_endpoint
endpoint = 'https://' + host
object_key = 'example-object'
expiration = 3600 # time in seconds
# hashing methods
def hash(key, msg):
return hmac.new(key, msg.encode('utf-8'), hashlib.sha256).digest()
# region is a wildcard value that takes the place of the AWS region value
# as COS doen't use regions like AWS, this parameter can accept any string
def createSignatureKey(key, datestamp, region, service):
keyDate = hash(('AWS4' + key).encode('utf-8'), datestamp)
keyRegion = hash(keyDate, region)
keyService = hash(keyRegion, service)
keySigning = hash(keyService, 'aws4_request')
return keySigning
# assemble the standardized request
time = datetime.datetime.utcnow()
timestamp = time.strftime('%Y%m%dT%H%M%SZ')
datestamp = time.strftime('%Y%m%d')
standardized_querystring = ('X-Amz-Algorithm=AWS4-HMAC-SHA256' +
'&X-Amz-Credential=' + access_key + '/' + datestamp + '/' + region + '/s3/aws4_request' +
'&X-Amz-Date=' + timestamp +
'&X-Amz-Expires=' + str(expiration) +
'&X-Amz-SignedHeaders=host')
standardized_querystring_url_encoded = quote(standardized_querystring, safe='&=')
standardized_resource = '/' + bucket + '/' + object_key
standardized_resource_url_encoded = quote(standardized_resource, safe='&')
payload_hash = 'UNSIGNED-PAYLOAD'
standardized_headers = 'host:' + host + '\n'
signed_headers = 'host'
standardized_request = (http_method + '\n' +
standardized_resource + '\n' +
standardized_querystring_url_encoded + '\n' +
standardized_headers + '\n' +
signed_headers + '\n' +
payload_hash)
# assemble string-to-sign
hashing_algorithm = 'AWS4-HMAC-SHA256'
credential_scope = datestamp + '/' + region + '/' + 's3' + '/' + 'aws4_request'
sts = (hashing_algorithm + '\n' +
timestamp + '\n' +
credential_scope + '\n' +
hashlib.sha256(standardized_request).hexdigest())
# generate the signature
signature_key = createSignatureKey(secret_key, datestamp, region, 's3')
signature = hmac.new(signature_key,
(sts).encode('utf-8'),
hashlib.sha256).hexdigest()
# create and send the request
# the 'requests' package autmatically adds the required 'host' header
request_url = (endpoint + '/' +
bucket + '/' +
object_key + '?' +
standardized_querystring_url_encoded +
'&X-Amz-Signature=' +
signature)
print 'request_url: %s' % request_url
print '\nSending `%s` request to IBM COS -----------------------' % http_method
print 'Request URL = ' + request_url
request = requests.put(request_url)
print '\nResponse from IBM COS ---------------------------------'
print 'Response code: %d\n' % request.status_code
print request.text
# this information can be helpful in troubleshooting, or to better
# understand what goes into signature creation
print 'These are the values used to construct this request.'
print 'Request details -----------------------------------------'
print 'http_method: %s' % http_method
print 'host: %s' % host
print 'region: %s' % region
print 'endpoint: %s' % endpoint
print 'bucket: %s' % bucket
print 'object_key: %s' % object_key
print 'timestamp: %s' % timestamp
print 'datestamp: %s' % datestamp
print 'Standardized request details ----------------------------'
print 'standardized_resource: %s' % standardized_resource_url_encoded
print 'standardized_querystring: %s' % standardized_querystring_url_encoded
print 'standardized_headers: %s' % standardized_headers
print 'signed_headers: %s' % signed_headers
print 'payload_hash: %s' % payload_hash
print 'standardized_request: %s' % standardized_request
print 'String-to-sign details ----------------------------------'
print 'credential_scope: %s' % credential_scope
print 'string-to-sign: %s' % sts
print 'signature_key: %s' % signature_key
print 'signature: %s' % signature
print 'Because the signature key has non-ASCII characters, it is'
print 'necessary to create a hexadecimal digest for the purposes'
print 'of checking against this example.'
def hex_hash(key, msg):
return hmac.new(key, msg.encode('utf-8'), hashlib.sha256).hexdigest()
def createHexSignatureKey(key, datestamp, region, service):
keyDate = hex_hash(('AWS4' + key).encode('utf-8'), datestamp)
keyRegion = hex_hash(keyDate, region)
keyService = hex_hash(keyRegion, service)
keySigning = hex_hash(keyService, 'aws4_request')
return keySigning
signature_key_hex = createHexSignatureKey(secret_key, datestamp, region, 's3')
print 'signature_key (hexidecimal): %s' % signature_key_hex
print 'Header details ------------------------------------------'
print 'pre-signed url: %s' % request_url
NodeJS Example
const crypto = require('crypto');
const moment = require('moment');
const https = require('https');
const accessKey = "{COS_HMAC_ACCESS_KEY_ID}";
const secretKey = "{COS_HMAC_SECRET_ACCESS_KEY}";
const httpMethod = 'GET';
const host = '{endpoint}';
const region = '';
const endpoint = 'https://' + host;
const bucket = 'example-bucket';
const objectKey = 'example-object'
const expiration = 86400 // time in seconds
// hashing and signing methods
function hash(key, msg) {
var hmac = crypto.createHmac('sha256', key);
hmac.update(msg, 'utf8');
return hmac.digest();
}
function hmacHex(key, msg) {
var hmac = crypto.createHmac('sha256', key);
hmac.update(msg, 'utf8');
return hmac.digest('hex');
}
function hashHex(msg) {
var hash = crypto.createHash('sha256');
hash.update(msg);
return hash.digest('hex');
}
// region is a wildcard value that takes the place of the AWS region value
// as COS doesn't use the same conventions for regions, this parameter can accept any string
function createSignatureKey(key, datestamp, region, service) {
keyDate = hash(('AWS4' + key), datestamp);
keyString = hash(keyDate, region);
keyService = hash(keyString, service);
keySigning = hash(keyService, 'aws4_request');
return keySigning;
}
function createHexSignatureKey(key, datestamp, region, service) {
keyDate = hashHex(('AWS4' + key), datestamp);
keyString = hashHex(keyDate, region);
keyService = hashHex(keyString, service);
keySigning = hashHex(keyService, 'aws4_request');
return keySigning;
}
function printDebug() {
// this information can be helpful in troubleshooting, or to better
// understand what goes into signature creation
console.log('These are the values used to construct this request.');
console.log('Request details -----------------------------------------');
console.log(`httpMethod: ${httpMethod}`);
console.log(`host: ${host}`);
console.log(`region: ${region}`);
console.log(`endpoint: ${endpoint}`);
console.log(`bucket: ${bucket}`);
console.log(`objectKey: ${objectKey}`);
console.log(`timestamp: ${timestamp}`);
console.log(`datestamp: ${datestamp}`);
console.log('Standardized request details ----------------------------');
console.log(`standardizedResource: ${standardizedResource}`);
console.log(`standardizedQuerystring: ${standardizedQuerystring}`);
console.log(`standardizedHeaders: ${standardizedHeaders}`);
console.log(`signedHeaders: ${signedHeaders}`);
console.log(`payloadHash: ${payloadHash}`);
console.log(`standardizedRequest: ${standardizedRequest}`);
console.log('String-to-sign details ----------------------------------');
console.log(`credentialScope: ${credentialScope}`);
console.log(`string-to-sign: ${sts}`);
console.log(`signatureKey: ${signatureKey}`);
console.log(`signature: ${signature}`);
console.log('Because the signature key has non-ASCII characters, it is');
console.log('necessary to create a hexadecimal digest for the purposes');
console.log('of checking against this example.');
signatureKeyHex = createHexSignatureKey(secretKey, datestamp, region, 's3')
console.log(`signatureKey (hexidecimal): ${signatureKeyHex}`);
console.log('Header details ------------------------------------------');
console.log(`pre-signed url: ${requestUrl}`);
}
// assemble the standardized request
var time = moment().utc();
var timestamp = time.format('YYYYMMDDTHHmmss') + 'Z';
var datestamp = time.format('YYYYMMDD');
var standardizedQuerystring = 'X-Amz-Algorithm=AWS4-HMAC-SHA256' +
'&X-Amz-Credential=' + encodeURIComponent(accessKey + '/' + datestamp + '/' + region + '/s3/aws4_request') +
'&X-Amz-Date=' + timestamp +
'&X-Amz-Expires=' + expiration.toString() +
'&X-Amz-SignedHeaders=host';
var standardizedResource = '/' + bucket + '/' + objectKey;
var payloadHash = 'UNSIGNED-PAYLOAD';
var standardizedHeaders = 'host:' + host;
var signedHeaders = 'host';
var standardizedRequest = httpMethod + '\n' +
standardizedResource + '\n' +
standardizedQuerystring + '\n' +
standardizedHeaders + '\n' +
'\n' +
signedHeaders + '\n' +
payloadHash;
// assemble string-to-sign
var hashingAlgorithm = 'AWS4-HMAC-SHA256';
var credentialScope = datestamp + '/' + region + '/' + 's3' + '/' + 'aws4_request';
var sts = hashingAlgorithm + '\n' +
timestamp + '\n' +
credentialScope + '\n' +
hashHex(standardizedRequest);
// generate the signature
signatureKey = createSignatureKey(secretKey, datestamp, region, 's3');
signature = hmacHex(signatureKey, sts);
// create and send the request
// the 'requests' package autmatically adds the required 'host' header
var requestUrl = endpoint + '/' +
bucket + '/' +
objectKey + '?' +
standardizedQuerystring +
'&X-Amz-Signature=' +
signature;
console.log(`requestUrl: ${requestUrl}`);
console.log(`\nSending ${httpMethod} request to IBM COS -----------------------`);
console.log('Request URL = ' + requestUrl);
// create and send the request
console.log(`\nSending ${httpMethod} request to IBM COS -----------------------`);
console.log('Request URL = ' + requestUrl);
var request = https.get(requestUrl, function (response) {
console.log('\nResponse from IBM COS ----------------------------------');
console.log(`Response code: ${response.statusCode}\n`);
response.on('data', function (chunk) {
console.log('Response: ' + chunk);
printDebug();
});
});
request.end();