VB.NETでのProduct Advertising API 署名認証
VB.NETでのProduct Advertising API 署名認証してみました。
いろいろなサンプルとかあるけど、VB.NETの完全なサンプル見つからないし、
わかりにくかったので、情報集めて、動くようにしました。
Amazonが署名認証導入してから、ハマっている人たくさんいそう。
VS.NET2008で作ってます。
まず、System.WEBを参照に追加。
次に以下のモジュールを追加
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Module ModuleAmazonAPI
Dim sAssociateTag As String = "[アソシエイトタグ]"
Dim sAccessKeyId As String = "[アクセスキーID]"
Dim sSecretAccessKey As String = "[シークレットアクセスキー]"
Public Function MakeAmazonRequest( _
ByVal sAssociateTag As String, _
ByVal sAccessKeyId As String, _
ByVal sSecretAccessKey As String, _
ByVal sSearchKeyWord As String) As String
Dim dictRequest As New Dictionary(Of String, String)
'リクエストパラメータをハッシュテーブルに保存
dictRequest("Service") = "AWSECommerceService"
dictRequest("Version") = "2008-04-07"
dictRequest("AssociateTag") = sAssociateTag
dictRequest("ContentType") = "Text/XML"
dictRequest("Operation") = "ItemSearch"
dictRequest("ResponseGroup") = "Small,ItemAttributes,Reviews,EditorialReview,Images,BrowseNodes,SalesRank,Offers"
dictRequest("AWSAccessKeyId") = sAccessKeyId
dictRequest("SearchIndex") = "All"
dictRequest("Keywords") = sSearchKeyWord
Dim dteNow As DateTime = DateTime.UtcNow
Dim sTimeStamp As String = dteNow.ToString("yyyy-MM-ddTHH:mm:ssZ")
'タイムスタンプはGMT
dictRequest("Timestamp") = sTimeStamp
Dim pc As New ParamComparer()
Dim sortedHash As New SortedDictionary(Of String, String)(dictRequest, pc)
' Get the canonical query string
Dim canonicalQS As String = ConstructCanonicalQueryString(sortedHash)
'以下の部分を追加
'============================
'GET
'ecs.amazonaws.jp
'/onca/xml
'============================
Dim builder As New System.Text.StringBuilder()
builder.Append("GET").Append(vbLf).Append(CStr("ecs.amazonaws.jp").ToLower()).Append(vbLf).Append("/onca/xml").Append(vbLf).Append(canonicalQS)
Dim stringToSign As String = builder.ToString()
Dim toSign As Byte() = System.Text.Encoding.UTF8.GetBytes(stringToSign)
Dim secret As Byte()
secret = System.Text.Encoding.UTF8.GetBytes(sSecretAccessKey)
Dim signer As System.Security.Cryptography.HMAC
signer = New Security.Cryptography.HMACSHA256(secret)
Dim sigBytes As Byte() = signer.ComputeHash(toSign)
Dim signature As String = Convert.ToBase64String(sigBytes)
Dim qsBuilder As New System.Text.StringBuilder()
qsBuilder.Append(" http://").Append("ecs.amazonaws.jp").Append("/onca/xml").Append("?").Append(canonicalQS).Append("&Signature=").Append(PercentEncodeRfc3986(signature))
Return qsBuilder.ToString()
End Function
Private Function PercentEncodeRfc3986(ByVal str As String) As String
str = System.Web.HttpUtility.UrlEncode(str, System.Text.Encoding.UTF8)
'str.Replace("'", "%27").Replace("(", "%28").Replace(")", "%29").Replace("*", "%2A").Replace("!", "%21").Replace("%7e", "~")
str = str.Replace("'", "%27").Replace("(", "%28").Replace(")", "%29").Replace("*", "%2A").Replace("!", "%21").Replace("%7e", "~").Replace("+", "%20")
Dim sbuilder As New System.Text.StringBuilder(str)
For i As Integer = 0 To sbuilder.Length - 1
If sbuilder(i) = "%"c Then
'コメント化
'If [Char].IsDigit(sbuilder(i + 1)) AndAlso [Char].IsLetter(sbuilder(i + 2)) Then
sbuilder(i + 1) = [Char].ToUpper(sbuilder(i + 1)) '日本語対策で追加
sbuilder(i + 2) = [Char].ToUpper(sbuilder(i + 2))
'End If
End If
Next
Return sbuilder.ToString()
End Function
Private Function ConstructCanonicalQueryString(ByVal sortedParamMap As SortedDictionary(Of String, String)) As String
Dim builder As New System.Text.StringBuilder()
If sortedParamMap.Count = 0 Then
builder.Append("")
Return builder.ToString()
End If
For Each kvp As KeyValuePair(Of String, String) In sortedParamMap
builder.Append(PercentEncodeRfc3986(kvp.Key))
builder.Append("=")
builder.Append(PercentEncodeRfc3986(kvp.Value))
builder.Append("&")
Next
Dim canonicalString As String = builder.ToString()
canonicalString = canonicalString.Substring(0, canonicalString.Length - 1)
Return canonicalString
End Function
Class ParamComparer
Implements IComparer(Of String)
Public Function Compare(ByVal p1 As String, ByVal p2 As String) As Integer Implements IComparer(Of String).Compare
Return String.CompareOrdinal(p1, p2)
End Function
End Class
End Module
**********************************************************************
使いかたは、
**********************************************************************
Dim sAssociateTag As String = "[アソシエイトタグ]"
Dim sAccessKeyId As String = "[アクセスキーID]"
Dim sSecretAccessKey As String = "[シークレットアクセスキー]"
Dim sURL as String
sURL = MakeAmazonRequest(sAssociateTag, sAccessKeyId, sSecretAccessKey, "ラーメンマン")
**********************************************************************
sURLでアクセスすれば、検索結果を得られます。
