Develop Reference

AWS TranslateText REST API call adding signature v4

Actually this is not a question, but an answer for those that are trying to use AWS TranslateText without SDK. I have had many problems until I got a running version.
In my opinion, the AWS documentation for this service is not complete and there are not many examples to check (at least for .Net).
At first, I thought I was not generating the correct V4 signature, but after checking the steps and values once again, I decided to use Postman to call the service. It was very helpful.
Postman can generate the AWS signature! (yeah, I did not know) so finally I noticed the signature value was not the problem.
Checking the request I could see the headers needed and some of its values.
The problem in my case was that I was not sending the "x-amz-target" header.
And by chance I found that the value for this header must be "AWSShineFrontendService_20170701.TranslateText"
(I saw a similar value here https://rdrr.io/cran/aws.translate/src/R/translateHTTP.R)
This other link was also helpful
Ivona Request Signing Issue - signature does not match (AWS Signature Version 4)
So now I have a running version, I want to share my .Net code. I hope it helps :) !!
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Web.Script.Serialization;
namespace AWS_TranslateTextTest
{
class AWS_TranslateText
{
// Replace this with your own values
const string AccessKey = "AKI_ADD_YOUR_ACCESSKEY";
const string SecretKey = "ADD_YOUR_SECRETKEY";
static void Main()
{
try
{
string text = "Translate this text from English to German.";
string sourceLang = "en";
string targetLang = "de";
string responseText = TranslateText(text, sourceLang, targetLang);
JObject json = JObject.Parse(responseText);
string translatedText = ""; // to do read response from json or responseText
if (json.ToString().Contains("TranslatedText")){
//To access to the properties in "dot" notation use a dynamic object
dynamic obj = json;
translatedText = obj.TranslatedText.Value;
Console.WriteLine("TranslatedText is: {0}", translatedText);
}
else{
Console.WriteLine("TranslatedText not found in response.");
throw new Exception(json.ToString());
}
}
catch (WebException ex)
{
Console.WriteLine(ex.Message);
if (ex.Response != null){
foreach (string header in ex.Response.Headers)
{
Console.WriteLine("{0}: {1}", header, ex.Response.Headers[header]);
}
using (var responseStream = ex.Response.GetResponseStream())
{
if (responseStream != null)
{
using (var streamReader = new StreamReader(responseStream))
{
Console.WriteLine(streamReader.ReadToEnd());
}
}
} }
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
private static string TranslateText(string text, string sourceLang, string targetLang)
{
var date = DateTime.UtcNow;
const string algorithm = "AWS4-HMAC-SHA256";
const string regionName = "eu-west-1";
const string serviceName = "translate";
const string method = "POST";
const string canonicalUri = "/";
const string canonicalQueryString = "";
const string x_amz_target_header = "AWSShineFrontendService_20170701.TranslateText";
const string contentType = "application/x-amz-json-1.1";
const string host = serviceName + "." + regionName + ".amazonaws.com";
var obj = new
{
SourceLanguageCode = sourceLang,
TargetLanguageCode = targetLang,
Text = text
};
var requestPayload = new JavaScriptSerializer().Serialize(obj);
var hashedRequestPayload = HexEncode(Hash(ToBytes(requestPayload)));
var dateStamp = date.ToString("yyyyMMdd");
var requestDate = date.ToString("yyyyMMddTHHmmss") + "Z";
var credentialScope = string.Format("{0}/{1}/{2}/aws4_request", dateStamp, regionName, serviceName);
var bytes = ToBytes(requestPayload);
var headers = new SortedDictionary<string, string>
{
{"content-length", bytes.Length.ToString()},
{"content-type", contentType},
{"host", host},
{"x-amz-date", requestDate},
{"x-amz-target", x_amz_target_header}
};
string canonicalHeaders =
string.Join("\n", headers.Select(x => x.Key.ToLowerInvariant() + ":" + x.Value.Trim())) + "\n";
string signedHeaders =
string.Join(";", headers.Select(x => x.Key.ToLowerInvariant() ));
// Task 1: Create a Canonical Request For Signature Version 4
var canonicalRequest = method + '\n' + canonicalUri + '\n' + canonicalQueryString +
'\n' + canonicalHeaders + '\n' + signedHeaders + '\n' + hashedRequestPayload;
var hashedCanonicalRequest = HexEncode(Hash(ToBytes(canonicalRequest)));
// Task 2: Create a String to Sign for Signature Version 4
// StringToSign = Algorithm + '\n' + RequestDate + '\n' + CredentialScope + '\n' + HashedCanonicalRequest
var stringToSign = string.Format("{0}\n{1}\n{2}\n{3}", algorithm, requestDate, credentialScope,
hashedCanonicalRequest);
// Task 3: Calculate the AWS Signature Version 4
// HMAC(HMAC(HMAC(HMAC("AWS4" + kSecret,"20130913"),"eu-west-1"),"tts"),"aws4_request")
byte[] signingKey = GetSignatureKey(SecretKey, dateStamp, regionName, serviceName);
// signature = HexEncode(HMAC(derived-signing-key, string-to-sign))
var signature = HexEncode(HmacSha256(stringToSign, signingKey));
// Task 4: Prepare a signed request
// Authorization: algorithm Credential=access key ID/credential scope, SignedHeadaers=SignedHeaders, Signature=signature
var authorization =
string.Format("{0} Credential={1}/{2}/{3}/{4}/aws4_request, SignedHeaders={5}, Signature={6}",
algorithm, AccessKey, dateStamp, regionName, serviceName, signedHeaders, signature);
// Send the request
string endpoint = "https://" + host; // + canonicalUri ;
var webRequest = WebRequest.Create(endpoint);
webRequest.Method = method;
webRequest.Timeout = 20000;
webRequest.ContentType = contentType;
webRequest.Headers.Add("X-Amz-Date", requestDate);
webRequest.Headers.Add("Authorization", authorization);
webRequest.Headers.Add("X-Amz-Target", x_amz_target_header);
webRequest.ContentLength = bytes.Length;
using (Stream newStream = webRequest.GetRequestStream())
{
newStream.Write(bytes, 0, bytes.Length);
newStream.Flush();
}
var response = (HttpWebResponse)webRequest.GetResponse();
using (Stream responseStream = response.GetResponseStream())
{
if (responseStream != null)
{
using (var streamReader = new StreamReader(responseStream))
{
string res = streamReader.ReadToEnd();
return res;
}
}
}
return null;
}
private static byte[] GetSignatureKey(String key, String dateStamp, String regionName, String serviceName)
{
byte[] kDate = HmacSha256(dateStamp, ToBytes("AWS4" + key));
byte[] kRegion = HmacSha256(regionName, kDate);
byte[] kService = HmacSha256(serviceName, kRegion);
return HmacSha256("aws4_request", kService);
}
private static byte[] ToBytes(string str)
{
return Encoding.UTF8.GetBytes(str.ToCharArray());
}
private static string HexEncode(byte[] bytes)
{
return BitConverter.ToString(bytes).Replace("-", string.Empty).ToLowerInvariant();
}
private static byte[] Hash(byte[] bytes)
{
return SHA256.Create().ComputeHash(bytes);
}
private static byte[] HmacSha256(String data, byte[] key)
{
return new HMACSHA256(key).ComputeHash(ToBytes(data));
}
}
}

Google API - Gmail. Downloading attachments

When calling this method please help by advising what values to pass through such as GmailService? Im guessing userID is the Gmail account and the messageID( i want to download all of them) .
How can i change this to download all the attachments in the inbox.
Thank you in advance and I hope someone can help me.
Method im using is below.
public static void GetAttachments(GmailService service, String userId, String messageId, String outputDir)
{
try
{
Message message = service.Users.Messages.Get(userId, messageId).Execute();
IList<MessagePart> parts = message.Payload.Parts;
foreach (MessagePart part in parts)
{
if (!String.IsNullOrEmpty(part.Filename))
{
String attId = part.Body.AttachmentId;
MessagePartBody attachPart = service.Users.Messages.Attachments.Get(userId, messageId, attId).Execute();
// Converting from RFC 4648 base64 to base64url encoding
// see http://en.wikipedia.org/wiki/Base64#Implementations_and_history
String attachData = attachPart.Data.Replace('-', '+');
attachData = attachData.Replace('_', '/');
byte[] data = Convert.FromBase64String(attachData);
File.WriteAllBytes(Path.Combine(outputDir, part.Filename), data);
}
}
}
catch (Exception e)
{
Console.WriteLine("An error occurred: " + e.Message);
}
}

I think the answer to your question can be solved using Get in PostMan
In your header in PostMan, use key as Authorization and pass your token generated to it as value
or goto Authorization and pick bearer token and pass your token.
Note that messageId is the Id in string of the message you are trying to fetch and {userId} =me or user according to google and I believe you can fetch Attachment Id by the method you use above.
https://www.googleapis.com/gmail/v1/users/me/messages/messageId/attachments/id
public async Task<TResult> GetGmailInboxAttachmentById<TResult>(string messageId, string token, string id, string attachId)
{
using (var httpClient = new HttpClient())
{
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
var url = "https://www.googleapis.com/gmail/v1/users/me/messages/" + messageId + "/" + id + "/attachments" + "/" + attachId;
HttpResponseMessage response = await httpClient.GetAsync(url);
return await response.Content.ReadAsAsync<TResult>();
}
}
foreach (var part in inbox.Payload.Parts)
{
if (!String.IsNullOrEmpty(part.Filename))
{
var attachId = part.Body.AttachmentId;
var attach = _gmailService.GetGmailInboxAttachmentById<MessagePartBody>(id, token, part.PartId, attachId).Result;
// Converting from RFC 4648 base64 to base64url encoding
// see http://en.wikipedia.org/wiki/Base64#Implementations_and_history
string attachData = attach.Data.Replace('_', '+');
attachData = attachData.Replace('_', '/');
byte[] data = Convert.FromBase64String(attachData);
string file = Convert.ToBase64String(data);
GetAttach.Add(file);
}
}
Hope this solve it for you because I solved it with this method

I know, it's could be an off-topic, but using PostMan in case when programmer use Google API is little but contraproductive :) APIs also have attachments.Get Method, and you will not need to call HTTP request and allow non OAuth 2.0 authentication especially when you're using multi-phase authentication.
Here is example:
https://developers.google.com/gmail/api/v1/reference/users/messages/attachments/get

foreach (var part in m.Payload.Parts)
{
if (!string.IsNullOrEmpty(part.Filename))
{
var attachId = part.Body.AttachmentId;
MessagePartBody attachPart = service.Users.Messages.Attachments.Get(userId,
message.Id,
attachId).Execute();
byte[] data = GetBytesFromPart(attachPart.Data);
File.WriteAllBytes(Path.Combine(#"c:\teste\",
$"{DateTime.Now:yyyyMMddHHmmss}-{part.Filename}"), data);
}
}
private static string DecodedString(string messagePart)
{
try
{
var data = GetBytesFromPart(messagePart);
string decodedString = Encoding.UTF8.GetString(data);
return decodedString;
}
catch (System.Exception e)
{
// ignored
return string.Empty;
}
}
private static byte[] GetBytesFromPart(string messagePart)
{
var attachData = messagePart.Replace('-', '+');
attachData = attachData.Replace('_', '/');
byte[] data = Convert.FromBase64String(attachData);
return data;
}

C# Make HttpWebResponse wait until response has been received instead of receiving HTTP 400 Error

I am trying to access Adobe's Datawarehouse reporting using their API. The way it works is by first forming the JSON using the metrics available and the dimensions you want it to be brojen down by. That all works fine. However where I do have the issue comes down to this. Whenever I request more than 3 to 4 dimensions, the report takes longer to generate. I would need the HttpWebResponse to wait until it has been completed before moving to the next line. Below is my sample code that I have built based on an example from github.
class Program
{
protected static string JSONFolder = System.Configuration.ConfigurationManager.AppSettings["JSONFolder"];
protected static string USERNAME = System.Configuration.ConfigurationManager.AppSettings["Username"];
protected static string SECRET = System.Configuration.ConfigurationManager.AppSettings["Secret"];
protected static string ReportSuiteID = System.Configuration.ConfigurationManager.AppSettings["ReportSuiteID"];
private static string ENDPOINT = "https://api5.omniture.com/admin/1.4/rest/";
protected static string environment = "dev";
static void Main(string[] args)
{
DateTime previousDay = DateTime.Today.AddDays(-1);
string json = RequestJsonBuilder(previousDay, previousDay, ReportSuiteID);
string response = callMethod("Report.Queue", json, 15);
var jss = new JavaScriptSerializer();
var requestDetails = jss.Deserialize<Dictionary<string, string>>(response);
}
/*Build the json for the methods Report.GetStatus and Report.Get*/
public static string RequestJsonBuilderStatus(string id)
{
ReportID json = new ReportID() { reportID = id };
var serializer = new JavaScriptSerializer();
var serializedResult = serializer.Serialize(json);
return serializedResult;
}
/*Build the json for the method Report.Queue*/
static string RequestJsonBuilder(DateTime StartDate, DateTime EndDate, string ReportSuiteID)
{
//Build the list of metrics to send with the request
var listMetrics = new List<Metrics>();
listMetrics.Add(new Metrics() { id = "visits" });
//Build the list of elements to send with the request
var listElements = new List<Elements>();
listElements.Add(new Elements() { id = "page" , top = "25"});
var serializer2 = new JavaScriptSerializer();
Dictionary<string, RankedRequest> dic = new Dictionary<string, RankedRequest>();
dic.Add("reportDescription", new RankedRequest()
{
reportSuiteID = ReportSuiteID,
dateFrom = StartDate.ToString("yyyy-MM-dd"),
dateTo = EndDate.ToString("yyyy-MM-dd"),
metrics = listMetrics,
elements = listElements,
source = "warehouse"
});
var serializedResult2 = serializer2.Serialize(dic);
return serializedResult2;
}
/*Build the rest call to the Adobe Analytics REST APII 1.4*/
public static String callMethod(String method, String data, int secs)
{
Program prog = new Program();
HttpWebResponse statusResponse = null;
string responseXml = "";
StringBuilder sbUrl = new StringBuilder(ENDPOINT + "?method=" + method);
HttpWebRequest omniRequest = (HttpWebRequest)WebRequest.Create(sbUrl.ToString());
string timecreated = generateTimestamp();
string nonce = generateNonce();
string digest = getBase64Digest(nonce + timecreated + SECRET);
nonce = base64Encode(nonce);
omniRequest.Headers.Add("X-WSSE: UsernameToken Username=\"" + USERNAME + "\", PasswordDigest=\"" + digest + "\", Nonce=\"" + nonce + "\", Created=\"" + timecreated + "\"");
omniRequest.Method = "POST";
omniRequest.ContentType = "text/json";
//Write the json details to the request
using (var streamWriter = new StreamWriter(omniRequest.GetRequestStream()))
{
string json = data;
Console.WriteLine("\n 2.0 ############## Json request : \n\n " + json + "\n\n");
streamWriter.Write(json);
}
//Get the response of the request
try
{
Console.WriteLine("\n 2.0 ############## Sleeping thread for " + secs + "\n");
using (HttpWebResponse statusResponse = (HttpWebResponse) omniRequest.GetResponse())
{
using (Stream receiveStream = statusResponse.GetResponseStream())
{
using (StreamReader readStream = new StreamReader(receiveStream, Encoding.UTF8))
{
responseXml = readStream.ReadToEnd();
return responseXml;
}
}
}
}
catch (Exception ex) { throw ex; }
}
// other methods defined below
// private static string getBase64Digest(string input)
// private static string generateNonce()
// public static string base64Encode(string data)
// etc.
}
How do I make HttpWebResponse wait until a HTTP 200 response is actually received. This might take minutes to sometimes an hour depending on the number of metrics and dimensions I add.
Things I have tried also include changing line 88 to something like this:
How to process WebResponse when .NET throws WebException ((400) Bad Request)?
how to wait until a web request with HttpWebRequest is finished?
Sincerely appreciate all help here.
Thanks

Did you try setting the timeout? I was looking recently for the similar question and found that one:
HttpWebRequest.GetResponse() keeps getting timed out

HMAC validation Failure with code 403

I have been exploring payeezy api from last three days. I am just making a simple http web request from a C# application. I have followed all the steps mentions and correctly verified each and everything. Below is the detail per item.
API Key :- I have verified my api key its correct.
API Secret :- It is also correct.
merchant token :- It is also verified.
Nonce :- I have created cryptographically strong random number as following.
RandomNumberGenerator rng = new RNGCryptoServiceProvider();
byte[] nonceData = new byte[18];
rng.GetBytes(nonceData);
string nonce = BitConverter.ToUInt64(nonceData,0).ToString();
Timestamp :-
string timestamp = Convert.ToInt64(ts.TotalMilliseconds).ToString();
Payload :-
{"merchant_ref":"Astonishing-Sale","transaction_type":"authorize","method":"credit_card","amount":"1299","currency_code":"USD","credit_card":{"type":"visa","cardholder_name":"John Smith","card_number":"4788250000028291","exp_date":"1020","cvv":"123"}}
Then I have created HMAC as following.
private string CreateAuthorization(string data, string secret)
{
// data is in following format.
// data = apiKey + nonce + timestamp + token + payload;
secret = secret ?? "";
using (var hmacsha256 = new HMACSHA256(Encoding.UTF8.GetBytes(secret)))
{
byte[] hashdata = hmacsha256.ComputeHash(Encoding.UTF32.GetBytes(data));
return Convert.ToBase64String(hashdata);
}
}
Now I am getting hmac validation error. My generated hmac string is 64 bit while on your website under docs and sandbox its 86 bit.
Can you please assist me in this as I am stuck on this issue from last three days.
Thanks

These are the common causes for “HMAC validation Failure”:
API key and/or API secret are incorrect.
Leading or trailing spaces in the API key, API secret, merchant token.
Timestamp in the HTTP header is not in milliseconds.
Timestamp in the HTTP header does not represent EPOCH time.
Timestamp in the HTTP header is not within 5 minutes of our server time.
System time is not accurate.
Here is a sample c# code to generate HMAC:
public byte[] CalculateHMAC(string data, string secret)
{
HMAC hmacSha256 = new HMACSHA256(Encoding.UTF8.GetBytes(secret));
byte[] dataBytes = Encoding.UTF8.GetBytes(data);
byte[] hmac2Hex = hmacSha256.ComputeHash(Encoding.UTF8.GetBytes(data));
string hex = BitConverter.ToString(hmac2Hex);
hex = hex.Replace("-","").ToLower();
byte[] hexArray = Encoding.UTF8.GetBytes(hex);
return hexArray;
}
protected void Button1_Click(object sender, EventArgs e)
{
string jsonString = "{ \"merchant_ref\": \"MVC Test\", \"transaction_type\": \"authorize\", \"method\": \"credit_card\", \"amount\": \"1299\", \"currency_code\": \"USD\", \"credit_card\": { \"type\": \"visa\", \"cardholder_name\": \"Test Name\", \"card_number\": \"4005519200000004\", \"exp_date\": \"1020\", \"cvv\": \"123\" } }";
Random random = new Random();
string nonce = (random.Next(0, 1000000)).ToString();
DateTime date = DateTime.UtcNow;
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
TimeSpan span = (date - epoch);
string time = span.TotalSeconds.ToString();
string token = Request.Form["token"];//Merchant token
string apiKey = Request.Form["apikey"];//apikey
string apiSecret = Request.Form["apisecret"];//API secret
string hashData = apiKey+nonce+time+token+jsonString;
string base64Hash = Convert.ToBase64String(CalculateHMAC(hashData, apiSecret));
string url = "https://api-cert.payeezy.com/v1/transactions";
//begin HttpWebRequest
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(url);
webRequest.Method = "POST";
webRequest.Accept = "*/*";
webRequest.Headers.Add("timestamp", time);
webRequest.Headers.Add("nonce", nonce);
webRequest.Headers.Add("token", token);
webRequest.Headers.Add("apikey", apiKey);
webRequest.Headers.Add("Authorization", base64Hash );
webRequest.ContentLength = jsonString.Length;
webRequest.ContentType = "application/json";
StreamWriter writer = null;
writer = new StreamWriter(webRequest.GetRequestStream());
writer.Write(jsonString);
writer.Close();
string responseString;
try
{
using(HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse())
{
using (StreamReader responseStream = new StreamReader(webResponse.GetResponseStream()))
{
responseString = responseStream.ReadToEnd();
request_label.Text = "<h3>Request</h3><br />" + webRequest.Headers.ToString() + System.Web.HttpUtility.HtmlEncode(jsonString);
response_label.Text = "<h3>Response</h3><br />" + webResponse.Headers.ToString() + System.Web.HttpUtility.HtmlEncode(responseString);
}
}
}
catch (WebException ex)
{
if (ex.Response != null)
{
using (HttpWebResponse errorResponse = (HttpWebResponse)ex.Response)
{
using (StreamReader reader = new StreamReader(errorResponse.GetResponseStream()))
{
string remoteEx = reader.ReadToEnd();
error.Text = remoteEx;
}
}
}
}
}

I've been working on an integration and it's working great; maybe you can take a peek
https://github.com/clifton-io/Clifton.Payment
Specifically you'll want to look here:
https://github.com/clifton-io/Clifton.Payment/blob/cc4053b0bfe05f2453dc508e96a649fc138b973c/Clifton.Payment/Gateway/Payeezy/PayeezyGateway.cs#L66
Best of luck :)

Invalid signature for signing requests to the Flickr API (simulation in console)

I'm trying to authenticate to the Flickr API for a demo application I want to make for myself. Then i will extend this app with new features that i'll learn of the Flick API's.
So this is just something i want to play with. But now I have some trouble in getting a request token.
I'm following the Flickr Authentication documentation here: Flickr Authentication
And i also found this Mathlabscript: Flickr API with OAuth-based user authentication
So based on these sources i have now the following console application:
class Program
{
private static string Secret = "2b2b2b2b2b2b2b2b2b";
private static string ConsumerKey = "1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a";
static void Main(string[] args)
{
Random rand = new Random();
string nonce = rand.Next(9999999).ToString();
string timestamp = ((int)(DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalSeconds).ToString();
Console.WriteLine("Nonce: " + nonce);
Console.WriteLine("TimeStamp: " + timestamp);
Console.WriteLine("ConsumerKey: " + ConsumerKey);
Console.WriteLine("AppSecret: " + Secret);
//request url
StringBuilder b = new StringBuilder();
b.Append("http://www.flickr.com/services/oauth/request_token");
b.Append("?");
b.Append("oauth_nonce=");
b.Append(nonce);
b.Append("&oauth_timestamp=");
b.Append(timestamp);
b.Append("&oauth_consumer_key=");
b.Append(ConsumerKey);
b.Append("&oauth_callback=oob");
b.Append("&oauth_signature_method=HMAC-SHA1");
string requesturl = b.ToString();
Console.WriteLine("RequestUrl: " + requesturl);
//base url
string basestring;
StringBuilder bs = new StringBuilder();
bs.Append("GET&");
bs.Append(UrlHelper.Encode("http://www.flickr.com/services/oauth/request_token")+"&");
basestring = bs.ToString();
StringBuilder p = new StringBuilder();
p.Append("oauth_callback=oob");
p.Append("&oauth_consumer_key=");
p.Append(ConsumerKey);
p.Append("oauth_nonce=");
p.Append(nonce);
p.Append("&oauth_signature_method=HMAC-SHA1");
p.Append("&oauth_timestamp=");
p.Append(timestamp);
string paramers = UrlHelper.Encode(p.ToString());
basestring += paramers;
Console.WriteLine("Basestring: " + basestring);
System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
string key = Secret + "&";
Console.WriteLine("Key: " + key);
byte[] keyByte = encoding.GetBytes(key);
//--create message to encrypt
byte[] messageBytes = encoding.GetBytes(basestring);
//--encrypt message using hmac-sha1 with the provided key
HMACSHA1 hmacsha1 = new HMACSHA1(keyByte);
byte[] hashmessage = hmacsha1.ComputeHash(messageBytes);
//--signature
string signature = ByteToString(hashmessage);
Console.WriteLine("Signature: " + signature);
Console.WriteLine("Final Request: " + requesturl + "&oauth_signature=" + signature);
Console.ReadKey(true);
}
public static string ByteToString(byte[] buff)
{
string sbinary = "";
for (int i = 0; i < buff.Length; i++)
{
sbinary += buff[i].ToString("X2"); // hex format
}
return (sbinary);
}
}
When i browse to the url this applications give me, i get the following response:
oauth_problem=signature_invalid&debug_sbs=GET&http%3A%2F%2Fwww.flickr.com%2Fservices%2Foauth%2Frequest_token&oauth_callback%3Dhttp%253A%252F%252Fwww.google.be%26oauth_consumer_key%3D1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a%26oauth_nonce%3D27504343%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1329469580
It seems that my signature for the request is invalid.
I hope someone can help me get the right signature for these requests.
I know there is a FlickNet Library that already did the hard work for most of the developers but i think it can be useful to get this working too. I looked into the source code of FlickrNet but didn't find the final peace to complete this code.
Let me know if you can help me. It would be so great!
Thanks!

Ok, I finally found the answer myself. Here are a few things you have to keep in mind when signing requests for oauth.
signature must be encrypted with HMAC-SHA1 using the basestring(see nr.2) as text to be encrypted and the clientsecret and the token_secret (if you have one) (see nr. 3)
basestring = [HttpMethod]&[FlickrAPIEndpoint]&[Parameters]
Key for request oauth_token = [ApiSecret]&
(or key = [ApiSecret]&[Oauth_token_secret] for request access_token)
IMPORTANT: FlickrAPIEndPoint and Parameters must be UrlEncoded (in two parts!)
I have used a separate class for the encoding because the HttpUtility.UrlEncode method uses lowercase encoding while the uppercase encoding should be used.
IMPORTANT: Parameters must be in alphabetical order!
Here's the code for a console application that will create a signed request for a request token and a request token secret.
class Program
{
private static string Secret = "9dcc18a121e9a02e";
private static string ConsumerKey = "3aafc63ec6b05f3f9a9ff3a1c35ce541";
private static string request_token = "";
static void Main(string[] args)
{
string requestString = "http://www.flickr.com/services/oauth/request_token";
//generate a random nonce and a timestamp
Random rand = new Random();
string nonce = rand.Next(999999).ToString();
string timestamp = GetTimestamp();
//create the parameter string in alphabetical order
string parameters = "oauth_callback=" + UrlHelper.Encode("http://www.example.com");
parameters += "&oauth_consumer_key=" + ConsumerKey;
parameters += "&oauth_nonce=" + nonce;
parameters += "&oauth_signature_method=HMAC-SHA1";
parameters += "&oauth_timestamp=" + timestamp;
parameters += "&oauth_version=1.0";
//generate a signature base on the current requeststring and parameters
string signature = generateSignature("GET", requestString, parameters);
//add the parameters and signature to the requeststring
string url = requestString + "?" + parameters + "&oauth_signature=" + signature;
//test the request
WebClient web = new WebClient();
string result = web.DownloadString(url);
Console.WriteLine("Flickr Response: ");
Console.WriteLine(result); //contains the oauth_token and the oauth_token_secret
Console.ReadKey(true);
}
private static string generateSignature(string httpMethod, string ApiEndpoint, string parameters)
{
//url encode the API endpoint and the parameters
//IMPORTANT NOTE:
//encoded text should contain uppercase characters: '=' => %3D !!! (not %3d )
//the HtmlUtility.UrlEncode creates lowercase encoded tags!
//Here I use a urlencode class by Ian Hopkins
string encodedUrl = UrlHelper.Encode(ApiEndpoint);
string encodedParameters = UrlHelper.Encode(parameters);
//generate the basestring
string basestring = httpMethod + "&" + encodedUrl + "&";
parameters = UrlHelper.Encode(parameters);
basestring = basestring + parameters;
//hmac-sha1 encryption:
System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
//create key (request_token can be an empty string)
string key = Secret + "&" + request_token;
byte[] keyByte = encoding.GetBytes(key);
//create message to encrypt
byte[] messageBytes = encoding.GetBytes(basestring);
//encrypt message using hmac-sha1 with the provided key
HMACSHA1 hmacsha1 = new HMACSHA1(keyByte);
byte[] hashmessage = hmacsha1.ComputeHash(messageBytes);
//signature is the base64 format for the genarated hmac-sha1 hash
string signature = System.Convert.ToBase64String(hashmessage);
//encode the signature to make it url safe and return the encoded url
return UrlHelper.Encode(signature);
}
//generator of unix epoch time
public static String GetTimestamp()
{
int epoch = (int)(DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalSeconds;
return epoch.ToString();
}
}
UrlHelper class by Ian Hopkins used for the url encoding
/// <summary>
/// URL encoding class. Note: use at your own risk.
/// Written by: Ian Hopkins (http://www.lucidhelix.com)
/// Date: 2008-Dec-23
/// (Ported to C# by t3rse (http://www.t3rse.com))
/// </summary>
public class UrlHelper
{
public static string Encode(string str)
{
var charClass = String.Format("0-9a-zA-Z{0}", Regex.Escape("-_.!~*'()"));
return Regex.Replace(str,
String.Format("[^{0}]", charClass),
new MatchEvaluator(EncodeEvaluator));
}
public static string EncodeEvaluator(Match match)
{
return (match.Value == " ") ? "+" : String.Format("%{0:X2}", Convert.ToInt32(match.Value[0]));
}
public static string DecodeEvaluator(Match match)
{
return Convert.ToChar(int.Parse(match.Value.Substring(1), System.Globalization.NumberStyles.HexNumber)).ToString();
}
public static string Decode(string str)
{
return Regex.Replace(str.Replace('+', ' '), "%[0-9a-zA-Z][0-9a-zA-Z]", new MatchEvaluator(DecodeEvaluator));
}
}

Are you writing this from scratch? If so, you shouldn't. Use http://flickrnet.codeplex.com/ instead. This library has already done the heavy lifting for you.