How to consume REST API (Liverail) via webservice using Java - api

I am a complete newbie to webservices but have some experience in Java. We have been provided with Liverail API documentation with a list of Entities that we can consume. This is what their doc says:
"Logical flow An API client must always use the /login method followed by the /set/entity method. All the remaining APIcalls will be executed on the selected entity. If you need to switch the current entity, you should use /unset/entity followed by a new /set/entity with the new entity ID as parameter. It is also recommended to call /logout once the API client ends its execution"
XML response format
The LiveRail API XML response is always formated like bellow.
My dilema is that i dont know how to make the GET calls.
What i would like to do in java is :
Create a http login to API webservices
Fetch a list of data (response is in XML format)
3 Convert this XML response into CSV file.
Any help will be highly appreciated.

Why not using RestTemplate?
final String uri = "http://localhost:8080/springrestexample/employees/{id}";
Map<String, String> params = new HashMap<String, String>();
params.put("id", "1");
RestTemplate restTemplate = new RestTemplate();
EmployeeVO result = restTemplate.getForObject(uri, EmployeeVO.class, params);
System.out.println(result);
Here is for more tutorials http://howtodoinjava.com/2015/02/20/spring-restful-client-resttemplate-example/

Related

How to send custom http response code back from spring cloud functions in gcp?

We are using the new gcp cloud functions using Java / Kotlin.
As in the current reference implementations, we are returning org.springframework.messaging.support.GenericMessage objects.
So our code looks like this (Kotlin):
fun generatePdfInBase64(message: Message<Map<String, Any>>): Message<*> {
val document = process(message)
val encoded = Base64.getEncoder().encodeToString(document.document)
return GenericMessage(encoded)
}
We were not able to find any way to include a custom http response code to our message, e.g. 201 or something. The function only responds 200 in case of no exception or 500.
Does someone know of a way to do this?
Best wishes
Andy
As it is mentioned at the official documentation, the HttpResponse class has a method called setStatusCode where you are able to set the number of the status as your convenience
For example:
switch (request.getMethod()) {
case "GET":
response.setStatusCode(HttpURLConnection.HTTP_OK);
writer.write("Hello world!");
break;
On the other hand the constructor of the GenericMessage receives as parameter a payload, therefore I think you can create a string with a json format and use the constructor for create your GenericMessage instance with the status response you need.
If you want to know more about the statuds codes take a look at this document.

How to acquire the response body from Apache HttpClient5's HttpResponse?

Getting the status code and response body was this easy in version 4:
StringEntity entity = new StringEntity(jsonData.toString());
HttpResponse r = org.apache.http.client.fluent.Request.Post(uri)
.connectTimeout(10*1000)
.socketTimeout(10*1000)
.addHeader("Content-Type", "application/json; charset=utf-8")
.body(entity)
.execute()
.returnResponse();
int status = r.getStatusLine().getStatusCode();
String body = EntityUtils.toString(r.getEntity(), "UTF-8");
return new CoolResponse(status, body);
But now in httpclient5 for some reason it isn't possible to get anything relating to the response body from an HttpResponse. Very confused by this. If I follow example 3 in their quickstart (https://hc.apache.org/httpcomponents-client-5.0.x/quickstart.html) it proposes I create an CloseableHttpClient, an HttpGet and a CloseableHttpResponse, but none of those allow you to set a connection timeout. Trying to find the best of both worlds but the options seem kind of scrambled here.
It's not mentioned in the quickstart, but in the fluent API you can follow up execute() with handleResponse() and pass it a lambda.
I wound up finding a much better article than the quickstart here:
https://ok2c.github.io/httpclient-migration-guide/migration-to-classic.html
Edit: that link is down, there is now an equivalent guide on apache's site
https://hc.apache.org/httpcomponents-client-5.2.x/migration-guide/migration-to-classic.html

How to get the current TraceId and SpanId

This article, https://devblogs.microsoft.com/aspnet/improvements-in-net-core-3-0-for-troubleshooting-and-monitoring-distributed-apps/, tells me that the field TraceId is available as a correlation id, which is great!
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
=> ConnectionId:0HLR1BR0PL1CH
=> RequestPath:/weatherforecastproxy
RequestId:0HLR1BR0PL1CH:00000001,
SpanId:|363a800a-4cf070ad93fe3bd8.,
TraceId:363a800a-4cf070ad93fe3bd8,
ParentId: Executed endpoint 'FrontEndApp.Controllers.WeatherForecastProxyController.Get
(FrontEndApp)'
In fact, I can see that in our log sink this works as advertised: When web application A serves a request and in doing so invokes web application B, both of them write the same TraceId value to the log.
As far as I understand, any ASP.NET Core application that receives an incoming Request-Id header will attach the same header to outgoing requests, but if the header does not exist on the incoming request, an new value will be generated for the outgoing request.
We have been asked to add that value to the response from web application A, but it is (not surprisingly) not available on the incoming request.
I have been looking at the System.Diagnostics.Activity class, but accessing Activity.Current isn't giving me an instance with anything useful - the TraceID is just {} - i.e. empty.
My question is this: How can I access the TraceId value in the context of a web application?
-S
I had the same problem when I tried to add a header with TraceId value.
Doing some tests with ModelValidation, I saw then in this kind of error response the "traceId" value was correct, but I couldn't obtain this value from http context variable in any way.
Then I went to net core source code to see DefaultProblemDetailsFactory implementation and surprise! The "traceId" value is obtained doing this:
var traceId = Activity.Current?.Id ?? httpContext?.TraceIdentifier;
Yes, you can get THE traceId using Activity static variable.
You can get tracid and spanid in dictionary.
using var subject = _tracer.BuildSpan($"Operation").StartActive();
var spanContext = subject.Span.Context;
var dictionary = new Dictionary<string, string>();
_tracer.Inject(spanContext, BuiltinFormats.TextMap, new TextMapInjectAdapter(dictionary));

Append URL Query Strings to request

I'm trying to send a POST request and format the query string in a specific format. Order doesn't matter aside from the first parameter, but I haven't been successful.
What I need:
localhost/someapp/api/dosomething/5335?save=false&userid=66462
What some of my attempts have spit out:
http://localhost/someapp/api/dosomething/?Id=29455&save=false&userId=797979
http://localhost/someapp/api/dosomething/?save=false&userId=797979
How I formatted the request:
request.AddQueryParameter("Id", "29455");
request.AddQueryParameter("save", "false");
request.AddQueryParameter("user", "4563533245");
If I try AddParameterfor Id it doesn't get appended on the query string (I'm thinking because it's a POST and not a GET), so that won't work. The API isn't expecting a form, it's expecting :
(string id, List<Dictionary<string,string>>)
I could use a StringBuilder, but that feels wrong. I'm not sure if UrlSegment is the best way to go either, since I would basically be hacking the query string. Is there a way to format my request in the format I need using RestSharp's API?
What I ended up using is UrlSegment and then kept the .AddQueryParameter methods, so the final code block looks like :
var url = new RestClient(localhost/someapp/api/dosomething/{id});
var request = new RestRequest(Method.POST);
request.AddParameter("Id", "5335", ParameterType.UrlSegment);
request.AddQueryParameter("save", "true");
request.AddQueryParameter("UserId", "5355234");
Which produced the URI I needed.
The easiest coding process for using RestSharp or any other API client library would be to use Postman to generate if you are unsure of how to code it. Download Postman, do a new request, enter the URL string to send to the API, click on Code, select C# (RestSharp) from the dropdown. Here is the code it generated.
var client = new RestClient("http://localhost/someapp/api/dosomething /5335?save=false&userid=66462");
var request = new RestRequest(Method.POST);
request.AddHeader("Postman-Token", "bd05aa45-f1b9-4665-a3e7-888ad16f2800");
request.AddHeader("cache-control", "no-cache");
IRestResponse response = client.Execute(request);

Authenticate in Xero from Salesforce

I'm new to Oauth and I stack on getting oauth_access_token to work with Xero. Web Service authentication doesn't work for me.
Xero returns the following error message "oauth_problem=signature_invalid&oauth_problem_advice=Failed to validate signature".
The generated signature is incorrect, but what is right way to generate it?
Here is APEX code which generates Endpoint. What is wrong?
Http h = new Http();
String consumer_key='XXX';
Long tmp=(System.now().getTime()/1000);
Blob isItCorrect = Crypto.generateMac('HMacSHA1', Blob.valueOf('https://api.xero.com/api.xro/2.0'), Blob.valueOf(consumer_key));
String signature= EncodingUtil.urlEncode(EncodingUtil.base64Encode(isItCorrect), 'UTF-8');
// Try to get access token
HttpRequest req = new HttpRequest();
req.setEndpoint('https://api.xero.com/oauth/RequestToken?oauth_consumer_key='+consumer_key+
'&oauth_signature_method=RSA-SHA1'+
'&oauth_signature='+signature+
'&oauth_timestamp='+tmp+ '&oauth_nonce='+tmp+'&oauth_version=1.0&scope=https%3A%2F%2Fapi.xero.com%2Fapi.xro%2F2.0');
req.setMethod('GET');
// Send the request, and return a response
HttpResponse res = h.send(req);
System.debug('~~~ '+res.getBody());
It generates following Endpoint:
Endpoint=https://api.xero.com/oauth/RequestToken?oauth_consumer_key=ICSP7Y5K2TG7RIIC6Y7R7KLC1AHWYC&oauth_signature_method=RSA-SHA1&oauth_signature=gWP02y2EIatw4xilTvd5Iq3e0%2Fw%3D&oauth_timestamp=1372123781&oauth_nonce=1372123781&oauth_version=1.0&scope=https%3A%2F%2Fapi.xero.com%2Fapi.xro%2F2.0
Just as an aside: I've never worked with salesforce so I'm not sure if there's a better
way to leverage existing oauth work on the platform, it's very rare
now to have to write all the oauth signature stuff yourself and it's
easy to make a mistake but here goes]
I think your signature base string is incorrect.
As far as I can tell you're just performing HMAC-SHA1 over https://api.xero.com/api.xro/2.0
if you read the OAuth Spec here: http://oauth.net/core/1.0/#anchor14 you need to construct the following base string (based on the request above)
GET&https%3A%2F%2Fapi.xero.com%2Foauth%2Frequesttoken&oauth_consumer_key%3DCONSUMER_KEY%26oauth_nonce (etc etc, just append all your query parameters apart from oauth_consumer as url encoded key=value pairs, in alphabetical order)
and then you need to create the hash with the key CONSUMER_KEY&CONSUMER_SECRET (both CONSUMER_KEY and CONSUMER_SECRET should be parameter encoded as per the OAuth Spec)
That should give you a valid signature..
Edit: I found this library which might be of help: https://code.google.com/p/sfdc-oauth-playground/