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in Opentelemetry, not able to get parent span

I am new to OpenTelemetry word. I have created spans for my services separately, but when i am try to combine spans of two different services, using context propogation, I am not able to do it successfully.
I have used following code:
// at client side:
public static void sendContext(String resource) {
TextMapSetter<HttpURLConnection> setter =
new TextMapSetter<HttpURLConnection>() {
#Override
public void set(HttpURLConnection carrier, String key, String value) {
carrier.setRequestProperty(key, value);
}
};
HttpURLConnection transportLayer = null;
String urlString = "http://127.0.0.1:8080" + resource;
try {
URL url = new URL(urlString);
transportLayer = (HttpURLConnection) url.openConnection();
} catch (MalformedURLException ex) {
System.out.println(ex.getMessage());
} catch (IOException e) {
System.out.println(e.getMessage());
}
GlobalOpenTelemetry.getPropagators()
.getTextMapPropagator()
.inject(Context.current(), transportLayer, setter);
}
// at server side:
public static Context getContext(HttpServletRequest request) {
TextMapGetter<HttpServletRequest> getter =
new TextMapGetter<HttpServletRequest>() {
#Override
public String get(HttpServletRequest carrier, String key) {
Enumeration<String> headerNames = carrier.getHeaderNames();
if (headerNames != null) {
while (headerNames.hasMoreElements()) {
String headerName = headerNames.nextElement();
System.out.println("headerNames.nextElement(): " + headerName);
if (headerName.equals(key)) {
String headerValue = request.getHeader(headerName);
System.out.println("headerValue): " + headerValue);
return headerValue;
}
}
}
return null;
}
#Override
public Iterable<String> keys(HttpServletRequest carrier) {
Set<String> set = new HashSet<String>();
Enumeration<String> headerNames = carrier.getHeaderNames();
if (headerNames != null) {
while (headerNames.hasMoreElements()) {
set.add(headerNames.nextElement());
}
}
return set;
}
};
Context extractedContext =
GlobalOpenTelemetry.getPropagators()
.getTextMapPropagator()
.extract(Context.current(), request, getter);
At server, i am not able to get parent span.
Kindly help on this.

You can refer to OpenTelemetry main documentation from here. It contains the context propagation part but I used HttpHeader type getter as the TextMapGetter with the same functionality which shows in the doc and instead of using
Scope scope = extractedContext.makeCurrent()
as the scope to create a child span, better to use directly without the scope,
tracer.spanBuilder(spanName).setParent(extractedContext)
Because sometimes the automated way to propagate the parent span on the current thread does not work fine.

NullPointerException while invoking method getInputParameters()

I am doing Parameterized Java Mapping in SAP PI 7.5 with following parameters bound by the tag names specified in the Operation Mapping
(BS_NAME,CHANNEL_NAME,EMAIL).
On testing the below java mapping in the test tab of OM using the payload, it gives the following error:
NullPointerException while trying to invoke the method com.sap.aii.mapping.api.TransformationInput.getInputParameters() of a null object loaded from field of an object loaded from local variable "this**"
I debugged the code but didn't found the issue, any suggestions?
Please find below Java code for XmlNFe_To_Mail Class. BodyText Class is also used to fetch some content. The error is encountered in the XmlNFe_To_Mail Class.
public class XmlNFe_To_Mail extends AbstractTransformation {
private String prefixoSubject = new String();
private String emailFrom = new String();
private String prefixoDocumento = new String();
private String frase = new String();
private String gap = "\n\r";
private AbstractTrace trace = null;
private Map map = null;
private String BSSystem = "";
private String ComChannel = "";
private String Emails = "";
private final String NFE_EMPRESA = "NFE Company: ";
private final String NFe = "NFE";
private final String NFe_Mail = "nfe#company.com";
TransformationInput input = null;
TransformationOutput output = null;
public void execute(InputStream in , OutputStream out) throws StreamTransformationException {
// TODO Auto-generated method stub
{
BSSystem = input.getInputParameters().getString("BS_NAME");
ComChannel = input.getInputParameters().getString("CHANNEL_NAME");
Emails = input.getInputParameters().getString("EMAIL");
try {
configParamEmail();
BufferedReader inpxml = new BufferedReader(new InputStreamReader( in ));
StringBuffer buffer = new StringBuffer();
String line = "";
String quebra = System.getProperty("line.separator");
while ((line = inpxml.readLine()) != null) {
line.replaceAll("\r\n", "");
line.replaceAll(quebra, "");
line.replaceAll(" />", "/>");
line.replaceAll(" />", "/>");
line.replaceAll(" />", "/>");
buffer.append(line);
}
String inptxml = buffer.toString();
inptxml = inptxml.replace("\r\n", "");
inptxml = inptxml.replaceAll(quebra, "");
inptxml = inptxml.replaceAll(" />", "/>");
inptxml = inptxml.replaceAll(" />", "/>");
inptxml = inptxml.replaceAll(" />", "/>");
String idNFe = "";
String numeroNF = "";
String idEvent = "";
idNFe = inptxml.substring(inptxml.indexOf("<chNFe>") + 7, inptxml.indexOf("</chNFe>"));
numeroNF = idNFe.substring(25, 34);
if (inptxml.indexOf("infEvento") > 0) {
idEvent = inptxml.substring(inptxml.indexOf("<tpEvento>") + 10, inptxml.indexOf("</tpEvento>"));
if (idEvent.length() > 0) {
if (idEvent.equals("111111")) {
this.setPrefixoDocumento(this.getPrefixoDocumento().replaceAll("NFE", "CancNFe"));
this.setPrefixoSubject(this.getPrefixoSubject().replaceAll("NFE", "NFE CANCELADA"));
} else if (idEvent.equals("100000")) {
this.setPrefixoDocumento(this.getPrefixoDocumento().replaceAll("NFE", "CCE"));
this.setPrefixoSubject(this.getPrefixoSubject().replaceAll("NFE", "CCE"));
} else {
this.setPrefixoDocumento(this.getPrefixoDocumento().replaceAll("NFE", "ManDest"));
this.setPrefixoSubject(this.getPrefixoSubject().replaceAll("NFE", "MANIFESTO"));
}
}
}
Channel chn = null;
RfcAccessor rfc = null;
String email = "";
String pdf = "";
chn = LookupService.getChannel(getBSystem(), getCChannel());
rfc = LookupService.getRfcAccessor(chn);
String req = "<ns0:TEST_NFE_MAIL_OPT xmlns:ns0='urn:sap-com:document:sap:rfc:functions'><I_ACCESS_KEY>" +
idNFe + "<I_ACCESS_KEY></ns0:ZOTC_NFE_EMAIL_OUTPUT>";
InputStream inputRFC = new ByteArrayInputStream(req.getBytes("UTF-8"));
XmlPayload rfcPayload = LookupService.getXmlPayload(inputRFC);
XmlPayload result = rfc.call(rfcPayload);
InputStream resp = result.getContent();
DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = builder.parse(resp);
Node node = (Node) doc.getElementsByTagName("E_EMAIL").item(0);
if (node.hasChildNodes() && !node.getFirstChild().getNodeValue().equals("")) {
email = node.getFirstChild().getNodeValue();
}
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
TransformerFactory tf = TransformerFactory.newInstance();
Transformer transform = tf.newTransformer();
Document docout = db.newDocument();
Element root = docout.createElement("ns0:Mail");
root.setAttribute("xmlns:ns0", "http://sap.com/xi/XI/Mail/30");
docout.appendChild(root);
Element subject = docout.createElement("Subject");
root.appendChild(subject);
Text subjectText = docout.createTextNode(getPrefixoSubject() + numeroNF);
subject.appendChild(subjectText);
Element from = docout.createElement("From");
root.appendChild(from);
Text fromText = docout.createTextNode(getEmailFrom());
from.appendChild(fromText);
if (email.length() > 0) {
email += ";";
} else {
email = this.getEmaillist();
}
Element to = docout.createElement("To");
root.appendChild(to);
Text toText = docout.createTextNode(email);
to.appendChild(toText);
Element contentType = docout.createElement("Content_Type");
root.appendChild(contentType);
Text contentTypeText = docout.createTextNode("multipart/mixed;boundary=--AaZz");
contentType.appendChild(contentTypeText);
BodyText texto = new BodyText(idNFe, getFrase(), inptxml, pdf);
Element content = docout.createElement("Content");
root.appendChild(content);
Text contentText = null;
if ("NFE Company: ".equalsIgnoreCase(getPrefixoSubject())) {
contentText = docout.createTextNode(texto.getnfeText());
} else if ("NFE CANCELADA Company: ".equalsIgnoreCase(getPrefixoSubject())) {
contentText = docout.createTextNode(texto.getCnfeText());
} else if ("CCE Company: ".equalsIgnoreCase(getPrefixoSubject())) {
contentText = docout.createTextNode(texto.getcceText());
}
content.appendChild(contentText);
DOMSource domS = new DOMSource(docout);
transform.transform((domS), new StreamResult(out));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (TransformerConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (TransformerException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// Exception Handling }
}
}
}
public String getGap() {
return gap;
}
public void setGap(String gap) {
this.gap = gap;
}
public String getFrase() {
return frase;
}
public void setFrase(String frase) {
this.frase = frase;
}
public String getBSystem() {
return BSSystem;
}
public String getEmaillist() {
return Emails;
}
public String getCChannel() {
return ComChannel;
}
public String getPrefixoSubject() {
return prefixoSubject;
}
public void setPrefixoSubject(String prefixoSubject) {
this.prefixoSubject = prefixoSubject;
}
public String getEmailFrom() {
return emailFrom;
}
public void setEmailFrom(String emailFrom) {
this.emailFrom = emailFrom;
}
public String getPrefixoDocumento() {
return prefixoDocumento;
}
public void setPrefixoDocumento(String prefixoDocumento) {
this.prefixoDocumento = prefixoDocumento;
}
private void configParamEmail() {
setEmailFrom(NFe_Mail);
setPrefixoDocumento(NFe);
setPrefixoSubject(NFE_EMPRESA);
}
#Override
public void transform(TransformationInput in , TransformationOutput out) throws StreamTransformationException {
this.execute( in .getInputPayload().getInputStream(), out.getOutputPayload().getOutputStream());
}
/*public void setParameter(Map arg0) {
// TODO Auto-generated method stub
}*/
}
Kindly let me know what changes should be done.
Thanks.

It's missing instance from the TransformationInput/TransformationOutput classes because their variables are null,
TransformationInput input = null;
TransformationOutput output = null;
So you need to instance them or pass them as reference on some setter.

What is proper practice for multithreading and httpclient in Java?

I'm creating a program that can do multiple logins. I will also give each login the ability to add an item to cart and purchase. The code is currently working for one account, and it's very basic. I had to trim out some private information, but the code should still be clear. Again, I'm just wondering what approach I should take for multiple logins? Does this code for the most part look optimal for speed? How do I approach a retry attempt if checkout returns 500? This code is currently setup for only a single login. Also, there weren't many articles I found to properly clean up the HttpClient. At least, I don't think the tutorials I found were very reputable.
Thanks again for taking the time to read this, I just want to learn other practices to improve my code and approach a proper multithreading technique.
Alittle more detail about my code, there is a token that is retrieved when you view the page, the token is stored and used throughout the program.
class example {
private static List<Header> headers = new ArrayList<Header>();
private static BasicCookieStore cookieStore = new BasicCookieStore();
private static CloseableHttpClient httpClient = HttpClientBuilder.create().setDefaultHeaders(headers).setDefaultCookieStore(cookieStore).build();
public static void main(String[] args) throws Exception {
String loginURL = "...";
String productUrl = "...";
String userid = "";
String password = "";
String formKey = "";
int size = 9;
Boolean debug = true;
JsonElement product;
headers.add(new BasicHeader("Host", "..."));
headers.add(new BasicHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"));
headers.add(new BasicHeader("Accept-Language", "en-us"));
headers.add(new BasicHeader("Content-Encoding", "gzip, deflate"));
headers.add(new BasicHeader("Content-Type", "Application/x-www-form-urlencoded"));
headers.add(new BasicHeader("User-Agent", "Mozilla/5.0 (iPhone; CPU iPhone OS 8_4_1 like Mac OS X) "
+ "AppleWebKit/600.1.4 (KHTML, like Gecko) Version/8.0 Mobile/12H321 Safari/600.1.4"));
headers.add(new BasicHeader("Connection", "keep-alive"));
Scanner in = new Scanner(System.in);
Gson gson = new Gson();
System.out.println("Select Profile\n1. ...\n2. Custom");
int select = in.nextInt();
switch(select) {
case 1:
userid = "...";
password = "...";
break;
// Custom Account Login
case 2:
System.out.println("Enter User_ID:");
userid = in.next();
System.out.println("Enter Password:");
password = in.next();
break;
}
int input = 0;
do {
input = in.nextInt();
switch(input) {
case 99:
debug = true;
break;
// View Menu.
case 0:
System.out.println("...");
break;
// Initiate Session
case 1:
// Retrieve formKey for login page.
formKey = getLogin(GetPageContent(loginURL));
session(formKey, userid, password, debug);
System.out.println("Press 0 to View Menu");
break;
case 2:
product = getProduct(GetPageContent(productUrl));
// Retrieve Product ID
Product productInfo = gson.fromJson(product.getAsJsonObject(), Product.class);
// Retrieve Color
Product[] color = gson.fromJson(product.getAsJsonObject().getAsJsonObject("attributes").getAsJsonObject("92").getAsJsonArray("options"), Product[].class);
// Prepare product request
String productKey = productInfo.getProductId();
String colorId = color[0].getId();
String postUrl = productInfo.getPostUrl();
// Execute addToCart
String result = addToCart(formKey, postUrl, productKey, colorId, size, debug);
break;
case 3:
String result2 = checkout(formKey);
break;
}
} while(input != 0);
}
public static void session(String formKey, String userid, String password, Boolean debug) {
HttpPost post = new HttpPost("...");
try {
// Package the data
StringEntity entity = new StringEntity("...");
post.setEntity(entity);
// Execute the data
HttpResponse response = httpClient.execute(post);
} catch (Exception e) {
e.printStackTrace();
} finally {
post.releaseConnection();
System.out.println("Login execution completed.");
}
}
public static String addToCart(String formKey, String postUrl, String productId, String colorId, int size, Boolean debug) {
String result = "";
HttpPost post = new HttpPost(postUrl);
try {
StringEntity entity = new StringEntity("...");
post.setEntity(entity);
// Execute the data
HttpResponse response = httpClient.execute(post);
System.out.println("Response Code : "
+ response.getStatusLine().getStatusCode());
// RETURN RESULT
result = EntityUtils.toString(response.getEntity());
if(debug) {
System.out.println("LOG: " + result);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
post.releaseConnection();
System.out.println("Adding to cart execution completed.");
}
return result;
}
public static String GetPageContent(String url) throws Exception {
StringBuffer result = null;
HttpGet request = new HttpGet(url);
try {
HttpResponse response = httpClient.execute(request);
int responseCode = response.getStatusLine().getStatusCode();
System.out.println("\nSending 'GET' request to URL : " + url);
System.out.println("Response Code : " + responseCode);
BufferedReader rd = new BufferedReader(
new InputStreamReader(response.getEntity().getContent()));
result = new StringBuffer();
String line = "";
while ((line = rd.readLine()) != null) {
result.append(line);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
request.releaseConnection();
}
return result.toString();
}
public static String getLogin(String html) {
String formKey = "";
Document doc = Jsoup.parse(html);
Element loginform = doc.getElementById("login-form");
Elements inputElements = loginform.getElementsByTag("input");
for (Element inputElement : inputElements) {
String key = inputElement.attr("name");
String value = inputElement.attr("value");
if (key.equals("form_key"))
formKey = value;
}
return formKey;
}
public static JsonObject getProduct(String html)
throws UnsupportedEncodingException {
Document doc = Jsoup.parse(html);
System.out.println("Extracting form's data...");
Element form = doc.getElementById("product_addtocart_form");
Elements formElements = form.getElementsByTag("input");
String rawScript = form.getElementsByTag("script").html();
String script = "{" + rawScript.substring(rawScript.lastIndexOf("g({") + 3, rawScript.indexOf("}});")) + "}}";
// Create JSON object
JsonElement jelement = new JsonParser().parse(script.trim());
JsonObject jobject = jelement.getAsJsonObject();
jobject = jobject.getAsJsonObject();
// Retrieve post link.
jobject.addProperty("postUrl", form.attr("action"));
return jobject;
}
public static String checkout(String formKey) {
HttpPost post = new HttpPost("...");
String result = "";
try {
StringEntity entity = new StringEntity("...");
post.setEntity(entity);
HttpResponse response = httpClient.execute(post);
int status = response.getStatusLine().getStatusCode();
if(status == 200) {
result = EntityUtils.toString(response.getEntity());
System.out.println("Checkout Result: " + result);
} else if(status == 302) {
System.out.println("Checkout failed, Code: 302.");
} else if(status == 404) {
System.out.println("Checkout failed, Code: 404.");
} else if(status == 500) {
(insert retry step here)
System.out.println("Webserver is probably down. Code, 500.");
}
} catch (Exception e) {
e.printStackTrace();
}
finally {
post.releaseConnection();
}
return result;
}
}

Subsequent httpClient calls return initial calls results

I have these methods in a class called HttpHelper. Now the initial call validates user credentials and returns true. That is expected. The next call is to register a user. That seems to go fine with no hiccups and is to return the new user ID. Instead of returning the user ID it returns true again. Almost like it is cached and just returning the result from the initial call. Anyone have any thoughts as to why this might occur?
private static CookieStore sCookieStore;
private static String invoke(HttpUriRequest request)
throws ClientProtocolException, IOException {
String result = null;
DefaultHttpClient httpClient = new DefaultHttpClient();
// restore cookie
if (sCookieStore != null) {
httpClient.setCookieStore((org.apache.http.client.CookieStore) sCookieStore);
}
//request.addHeader("Host", "localhost");
HttpResponse response = httpClient.execute(request);
StringBuilder builder = new StringBuilder();
BufferedReader reader = new BufferedReader(new InputStreamReader(
response.getEntity().getContent()));
for (String s = reader.readLine(); s != null; s = reader.readLine()) {
builder.append(s);
}
result = builder.toString();
Log.d(TAG, "result is ( " + result + " )");
// store cookie
sCookieStore = (CookieStore) ((AbstractHttpClient) httpClient).getCookieStore();
return result;
}
public static String invokeGet(String action, List<NameValuePair> params) {
try {
StringBuilder sb = new StringBuilder(API_URL);
sb.append(action);
if (params != null) {
for (NameValuePair param : params) {
sb.append("?");
sb.append(param.getName());
sb.append("=");
sb.append(param.getValue());
}
}
Log.d(TAG, "url is" + sb.toString());
//HttpGet httpGet = new HttpGet(URLEncoder.encode(sb.toString(), "UTF-8"));
HttpGet httpGet = new HttpGet(sb.toString());
return invoke(httpGet);
} catch (Exception e) {
Log.e(TAG, e.toString());
}
return null;
}
public static String invokeGet(String action) {
return invokeGet(action, null);
}
Here are the calls I am making. As specified above the authResult variable would result in a string result of true. The nextResult should hold the user ID value but instead holds the value true like from the initial request:
String authResult = HttpHelper.invokeGet("<url to validate user>");
if (this.URL.indexOf("register") > -1)
String nextResult = HttpHelper.invokeGet(this.URL);
else
String nextResult = HttpHelper.invokeGet(this.URL);
UPDATED: added in the sCookieStore variable.
UPDATED 2: adding in the methods that are being called via the API (MVC .NET):
authResult variable would get this result:
public bool Get(String userName, String userPassword)
{
Task<IdentityUser> iu = _repo.FindUser(userName, userPassword);
if (iu != null)
{
FormsAuthentication.SetAuthCookie(userName, false);
return true;
}
return false;
}
nextResult variable should get this result:
[HttpGet]
[AllowAnonymous]
public async Task<IHttpActionResult> RegisterUser(String userName, String userPassword, String huh)
{
UserModel userModel = new UserModel();
userModel.ConfirmPassword = userPassword;
userModel.UserName = userName;
userModel.Password = userPassword;
String userID = "";
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
IdentityResult result = await _repo.RegisterUser(userModel);
IHttpActionResult errorResult = GetErrorResult(result);
if (errorResult != null)
{
return errorResult;
}
else
{
Task<IdentityUser> iu = _repo.FindUser(userModel.UserName, userModel.Password);
using (var context = new AuthContext())
{
var userStore = new UserStore<IdentityUser>(context);
var userManager = new UserManager<IdentityUser>(userStore);
userID = iu.Result.Id;
result = await userManager.AddToRoleAsync(userID, "Users");
errorResult = GetErrorResult(result);
if (errorResult != null)
{
return errorResult;
}
}
}
return Ok("userID:" + userID);
}

It looks like authResult is going to fire invokeGet 2 times, giving it the same argument (this.URL). Within invokeGet, the variable sb is going to be this.URL both times the function fires.
This is a bit curious to me:
// restore cookie
if (sCookieStore != null) {
httpClient.setCookieStore((org.apache.http.client.CookieStore) sCookieStore);
}
then at the end,
// store cookie
sCookieStore = (CookieStore) ((AbstractHttpClient) httpClient).getCookieStore();
When is sCookieStore defined? It could be that the cookies aren't being handled correctly and you're making two fresh connections. If getting and setting the cookies is the issue, it might be better to get a cookie if it exists at the beginning of invoke, then set the new one at the end.

LinkedIn integration - Establish a requestToken

I'm developing (trying for now) portlet that will be integrated with LinkedIn.
Following the documentation about it:
http://developer.linkedin.com/docs/DOC-1008 -->
The first step to authorizing a LinkedIn member is requesting a requestToken. This request is done with an HTTP POST.
For the requestToken step, the following components should be present in your string to sign:
* HTTP Method (POST)
* Request URI (https://api.linkedin.com/uas/oauth/requestToken)
* oauth_callback
* oauth_consumer_key
* oauth_nonce
* oauth_signature_method
* oauth_timestamp
* oauth_version
I have already API(it's oauth_consumer_key) key and i need to generate specific URL string.
Have next java code for this URL and HTTP connection:
private void processAuthentication() {
Calendar cal = Calendar.getInstance();
Long ms = cal.getTimeInMillis();
Long timestamp = ms / 1000;
Random r = new Random();
Long nonce = r.nextLong();
String prefixUrl = "https://api.linkedin.com/uas/oauth/requestToken";
String oauthCallback = "oauth_callback=http://localhost/";
String oauthConsumerKey =
"&oauth_consumer_key=my_consumer_key";
String oauthNonce = "&oauth_nonce=" + nonce.toString();
String oauthSignatureMethod = "&oauth_signature_method=HMAC-SHA1";
String oauthTimestamp = "&oauth_timestamp=" + timestamp.toString();
String oauthVersion = "&oauth_version=1.0";
String mainUrl =
oauthCallback + oauthConsumerKey + oauthNonce + oauthSignatureMethod
+ oauthTimestamp + oauthVersion;
try {
prefixUrl =
URLEncoder.encode(prefixUrl, "UTF-8") + "&"
+ URLEncoder.encode(mainUrl, "UTF-8");
URL url = new URL(prefixUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
String msg = connection.getResponseMessage();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
The question is next,for those, who had faced this problem:
How should really look URL string for connection and how response is received?
For URL, it's interested the example of URL, you generated.
And for response interested, method to get it.
As i understand, after HTTP connection been established,that response is:
connection.getResponseMessage();

#sergionni I found answer to your Question from linkedin-developer
As you know
The first step to authorizing a Linked-In member is requesting a requestToken. This request is done with an HTTP POST.
Your base string should end up looking something like this if you're using a callback:
POST&https%3A%2F%2Fapi.linkedin.com%2Fuas%2Foauth%2FrequestToken
&oauth_callback%3Dhttp%253A%252F%252Flocalhost%252Foauth_callback%26o
auth_consumer_key%3DABCDEFGHIJKLMNOPQRSTUVWXYZ%26
oauth_nonce%3DoqwgSYFUD87MHmJJDv7bQqOF2EPnVus7Wkqj5duNByU%26
oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1259178158%26
oauth_version%3D1.0
You then sign this base string with your consumer_secret, computing a signature. In this case, if your secret was 1234567890, the signature would be TLQXuUzM7omwDbtXimn6bLDvfF8=.
Now you take the signature you generated, along with oauth_nonce, oauth_callback, oauth_signature_method, oauth_timestamp, oauth_consumer_key, and oauth_version and create an HTTP Authorization header. For this request, that HTTP header would look like:
Authorization: OAuth
oauth_nonce="oqwgSYFUD87MHmJJDv7bQqOF2EPnVus7Wkqj5duNByU",
oauth_callback="http%3A%2F%2Flocalhost%2Foauth_callback",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="1259178158",
oauth_consumer_key="ABCDEFGHIJKLMNOPQRSTUVWXYZ",
oauth_signature="TLQXuUzM7omwDbtXimn6bLDvfF8=",
oauth_version="1.0"
Please note, that the HTTP header is a single header -- not an HTTP header for each component. You can optionally supply a realm="http://api.linkedin.com".
As a response to your request for a requestToken, your requestToken will be in the "oauth_token" response field, a validation that we acknowledged your callback with the "oauth_callback_confirmed" field, an oauth_token_secret, and a oauth_expires_in, and a few other values.
(here us Your answaer) response would look like:
oauth_token=94ab03c4-ae2c-45e4-8732-0e6c4899db63
&oauth_token_secret=be6ccb24-bf0a-4ea8-a4b1-0a70508e452b
&oauth_callback_confirmed=true&oauth_expires_in=599

You might try out the OAuth libraries to handle the connection: http://code.google.com/p/oauth/

I created a plugin for Play Framework to easily integrated with LinkedIn's OAuth: geeks.aretotally.in/projects/play-framework-linkedin-module. Hopefully it can help. You should def check out Play, very very cool Java framework.

portlet body:
public class LinkedInPortlet extends GenericPortlet {
public static final String PAGE_PIN = "pin";
public static final String PAGE_EDIT = "edit";
public static final String PAGE_PROFILE = "profile";
public static final String PAGE_CONNECTIONS = "connections";
public static final String FORM_LINKEDIN_PREFERENCES = "preferencesLinkedInForm";
public static final String PAGE_VIEW_MY_PROFILE = "/WEB-INF/portlets/linkedin/myProfile.jsp";
public static final String PAGE_VIEW_MY_CONNECTIONS =
"/WEB-INF/portlets/linkedin/myConnections.jsp";
public static final String PAGE_PREFERENCES = "/WEB-INF/portlets/linkedin/edit.jsp";
public void doView(RenderRequest request, RenderResponse response) throws PortletException,
IOException {
String view = PAGE_VIEW_MY_PROFILE;
String page =
(String) request.getPortletSession().getAttribute(
"page_" + getPortletIdentifier(request), PortletSession.PORTLET_SCOPE);
String accessTokenToken =
getStringConfiguration(request, LinkedInPreferencesForm.PARAM_ACCESS_TOKEN_TOKEN);
String accessTokenSecret =
getStringConfiguration(request, LinkedInPreferencesForm.PARAM_ACCESS_TOKEN_SECRET);
LinkedInContact profile = new LinkedInContact();
List<LinkedInContact> contacts = new ArrayList<LinkedInContact>();
if (PAGE_PIN.equals(page)) {
view = PAGE_PREFERENCES;
} else if (PAGE_EDIT.equals(page)) {
view = PAGE_PREFERENCES;
} else if (PAGE_CONNECTIONS.equals(page)) {
try {
contacts =
ServiceResolver.getResolver().getLinkedInService().getConnections(
accessTokenToken, accessTokenSecret);
} catch (ServiceException se) {
view = PAGE_PREFERENCES;
handleException(request, se);
}
view = PAGE_VIEW_MY_CONNECTIONS;
} else {
try {
profile =
ServiceResolver.getResolver().getLinkedInService().getProfile(
accessTokenToken, accessTokenSecret);
} catch (ServiceException se) {
view = PAGE_PREFERENCES;
handleException(request, se);
}
view = PAGE_VIEW_MY_PROFILE;
}
request.setAttribute("profile", profile);
request.setAttribute("contacts", contacts);
response.setContentType(request.getResponseContentType());
PortletRequestDispatcher rd = getPortletContext().getRequestDispatcher(view);
rd.include(request, response);
}
public void processAction(ActionRequest request, ActionResponse response)
throws PortletException, IOException {
String action;
action = (String) request.getParameter("action");
String page = request.getParameter("page");
if (page == null) {
page = PAGE_PROFILE;
} else if ("auth".equals(action)) {
request.getPortletSession().setAttribute(
"requestToken_" + getPortletIdentifier(request),
ServiceResolver.getResolver().getLinkedInService().getRequestToken(),
PortletSession.APPLICATION_SCOPE);
LinkedInPreferencesForm form = new LinkedInPreferencesForm(request);
request.getPortletSession().setAttribute(
FORM_LINKEDIN_PREFERENCES + getPortletIdentifier(request), form,
PortletSession.APPLICATION_SCOPE);
response.setPortletMode(PortletMode.EDIT);
} else if ("save".equals(action)) {
try {
try {
savePreferences(request, response);
} catch (ServiceException e) {
handleException(request, e);
}
} catch (PortletModeException e) {
handleException(request, e);
}
} else if ("myProfile".equals(action)) {
page = PAGE_PROFILE;
} else if ("myConnections".equals(action)) {
page = PAGE_CONNECTIONS;
}
if (page != null) {
request.getPortletSession().setAttribute("page_" + getPortletIdentifier(request), page,
PortletSession.PORTLET_SCOPE);
}
}
private void savePreferences(ActionRequest request, ActionResponse response)
throws PortletModeException, ServiceException {
LinkedInPreferencesForm form = new LinkedInPreferencesForm(request);
if (validateForm(request, form)) {
LinkedInRequestToken requestToken =
(LinkedInRequestToken) request.getPortletSession().getAttribute(
"requestToken_" + getPortletIdentifier(request),
PortletSession.APPLICATION_SCOPE);
String pin = request.getParameter("pinCode");
LinkedInAccessToken accessToken;
try {
accessToken =
ServiceResolver.getResolver().getLinkedInService().getAccessToken(
requestToken, pin);
} catch (LinkedInOAuthServiceException ase) {
response.setPortletMode(PortletMode.EDIT);
throw new ServiceException("linkedin.authentication.failed");
}
String tokenToken = requestToken.getToken();
String secret = requestToken.getTokenSecret();
String tokenURL = requestToken.getAuthorizationUrl();
Properties configuration = new Properties();
configuration.setProperty(LinkedInPreferencesForm.PARAM_PIN, form.getPin());
configuration
.setProperty(LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_TOKEN, tokenToken);
configuration.setProperty(LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_SECRET, secret);
configuration.setProperty(LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_URL, tokenURL);
configuration.setProperty(LinkedInPreferencesForm.PARAM_ACCESS_TOKEN_TOKEN, accessToken
.getToken());
configuration.setProperty(LinkedInPreferencesForm.PARAM_ACCESS_TOKEN_SECRET,
accessToken.getTokenSecret());
ServiceResolver.getResolver().getPortalService().savePortletConfiguration(request,
configuration);
resetSessionForm(request, FORM_LINKEDIN_PREFERENCES);
response.setPortletMode(PortletMode.VIEW);
} else {
// store in session
request.getPortletSession().setAttribute(
FORM_LINKEDIN_PREFERENCES + getPortletIdentifier(request), form,
PortletSession.APPLICATION_SCOPE);
response.setPortletMode(PortletMode.EDIT);
logger.debug(FORM_LINKEDIN_PREFERENCES + " is in edit mode");
}
}
#Override
protected void addConfiguration(MessageSource messageSource, Locale locale,
Map<String, String> result) {
result.put(LinkedInPreferencesForm.PARAM_PIN, messageSource.getMessage(
"linkedIn.preferences.pin", null, locale));
result.put(LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_TOKEN, messageSource.getMessage(
"linkedIn.preferences.requestTokenToken", null, locale));
result.put(LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_SECRET, messageSource.getMessage(
"linkedIn.preferences.requestTokenSecret", null, locale));
result.put(LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_URL, messageSource.getMessage(
"linkedIn.preferences.requestTokenURL", null, locale));
result.put(LinkedInPreferencesForm.PARAM_ACCESS_TOKEN_TOKEN, messageSource.getMessage(
"linkedIn.preferences.accessToken", null, locale));
result.put(LinkedInPreferencesForm.PARAM_ACCESS_TOKEN_SECRET, messageSource.getMessage(
"linkedIn.preferences.accessTokenSecret", null, locale));
}
#Override
protected void addPreference(MessageSource messageSource, Locale locale,
Map<String, String> result) {
}
#Override
public String getAsyncTitle(RenderRequest request) {
return this.getTitle(request);
}
protected boolean validateForm(ActionRequest request, LinkedInPreferencesForm form) {
return form.validate();
}
protected String myEdit(RenderRequest request, RenderResponse response)
throws PortletException, IOException {
LinkedInPreferencesForm form = new LinkedInPreferencesForm();
form.setPin(getStringConfiguration(request, LinkedInPreferencesForm.PARAM_PIN));
form.setRequestTokenToken(getStringConfiguration(request,
LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_TOKEN));
form.setRequestTokenSecret(getStringConfiguration(request,
LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_SECRET));
form.setRequestTokenURL(getStringConfiguration(request,
LinkedInPreferencesForm.PARAM_REQUEST_TOKEN_URL));
registerSessionForm(request, FORM_LINKEDIN_PREFERENCES, form);
LinkedInRequestToken requestToken;
requestToken =
(LinkedInRequestToken) request.getPortletSession().getAttribute(
"requestToken_" + getPortletIdentifier(request),
PortletSession.APPLICATION_SCOPE);
if (requestToken == null) {
requestToken =
new LinkedInRequestToken(form.getRequestTokenToken(), form
.getRequestTokenSecret());
requestToken.setAuthorizationUrl(form.getRequestTokenURL());
}
request.setAttribute("requestToken", requestToken);
return PAGE_PREFERENCES;
}
}