16:26
Product Advertising APIの日本用Restクライアント(Java)
dankogaiさんが、PerlのProduct Advertising APIライブラリを作ってた。便乗して、Java。
Amazonの新しいProduct Advertising APIのRestのリクエストの作り方は前回のエントリで説明しました。このRestクライアントは、Amazonのドキュメントに載っています。しかし、その例は米国用になっているので、ちょっとだけ修正してあげる必要が在ります。
具体的には、endpointをecs.amazonaws.jpに変更します。これだけで、日本のものに適用出来るようになります。なお、使用方法ですが、次のようにします。簡単ですね。
// リクエストのキーと値のMap
Map<String, String> keyMap = new HashMap<String, String>();
keyMap.put("AWSAccessKeyId", "000000000000000");
keyMap.put("Version", "2008-08-19");
keyMap.put("Operation", "ItemLookup");
keyMap.put("ItemId", "4877712399");
keyMap.put("ResponseGroup", "Medium");
keyMap.put("AssociateTag", "jx-22");
keyMap.put("Service", "AWSECommerceService");
SignedRequestsHelper signedRequestsHelper = new SignedRequestsHelper();
String urlStr = signedRequestsHelper.sign(keyMap);
URL url = new URL(urlStr);
HttpURLConnection connection = (HttpURLConnection) url
.openConnection();
日本用に修正したJava Rest クライアント
package com.amazon.associates.sample;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Iterator;
import java.util.Map;
import java.util.SortedMap;
import java.util.TimeZone;
import java.util.TreeMap;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import net.jirox.shohyo.exception.ShohyoFatalException;
import org.apache.commons.codec.binary.Base64;
public class SignedRequestsHelper {
private static final String UTF8_CHARSET = "UTF-8";
private static final String HMAC_SHA256_ALGORITHM = "HmacSHA256";
private static final String REQUEST_URI = "/onca/xml";
private static final String REQUEST_METHOD = "GET";
//日本用
private String endpoint = "ecs.amazonaws.jp"; // must be lowercase
private String awsAccessKeyId = "YOUR ACCESS KEY ID";
private String awsSecretKey = "YOUR SECRET KEY";
private SecretKeySpec secretKeySpec = null;
private Mac mac = null;
public SignedRequestsHelper() throws ShohyoFatalException {
byte[] secretyKeyBytes;
try {
secretyKeyBytes = awsSecretKey.getBytes(UTF8_CHARSET);
secretKeySpec = new SecretKeySpec(secretyKeyBytes,
HMAC_SHA256_ALGORITHM);
mac = Mac.getInstance(HMAC_SHA256_ALGORITHM);
mac.init(secretKeySpec);
} catch (UnsupportedEncodingException e) {
throw new ShohyoFatalException(e);
} catch (NoSuchAlgorithmException e) {
throw new ShohyoFatalException(e);
} catch (InvalidKeyException e) {
throw new ShohyoFatalException(e);
}
}
public String sign(Map<String, String> params) {
params.put("AWSAccessKeyId", awsAccessKeyId);
params.put("Timestamp", timestamp());
SortedMap<String, String> sortedParamMap = new TreeMap<String, String>(
params);
String canonicalQS = canonicalize(sortedParamMap);
String toSign = REQUEST_METHOD + "\n" + endpoint + "\n" + REQUEST_URI
+ "\n" + canonicalQS;
String hmac = hmac(toSign);
String sig = percentEncodeRfc3986(hmac);
String url = "http://" + endpoint + REQUEST_URI + "?" + canonicalQS
+ "&Signature=" + sig;
return url;
}
private String hmac(String stringToSign) {
String signature = null;
byte[] data;
byte[] rawHmac;
try {
data = stringToSign.getBytes(UTF8_CHARSET);
rawHmac = mac.doFinal(data);
Base64 encoder = new Base64();
signature = new String(encoder.encode(rawHmac));
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(UTF8_CHARSET + " is unsupported!", e);
}
return signature;
}
private String timestamp() {
String timestamp = null;
Calendar cal = Calendar.getInstance();
DateFormat dfm = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
dfm.setTimeZone(TimeZone.getTimeZone("GMT"));
timestamp = dfm.format(cal.getTime());
return timestamp;
}
private String canonicalize(SortedMap<String, String> sortedParamMap) {
if (sortedParamMap.isEmpty()) {
return "";
}
StringBuffer buffer = new StringBuffer();
Iterator<Map.Entry<String, String>> iter = sortedParamMap.entrySet()
.iterator();
while (iter.hasNext()) {
Map.Entry<String, String> kvpair = iter.next();
buffer.append(percentEncodeRfc3986(kvpair.getKey()));
buffer.append("=");
buffer.append(percentEncodeRfc3986(kvpair.getValue()));
if (iter.hasNext()) {
buffer.append("&");
}
}
String cannoical = buffer.toString();
return cannoical;
}
private String percentEncodeRfc3986(String s) {
String out;
try {
out = URLEncoder.encode(s, UTF8_CHARSET).replace("+", "%20")
.replace("*", "%2A").replace("%7E", "~");
} catch (UnsupportedEncodingException e) {
out = s;
}
return out;
}
}
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