Develop Reference

AWS SSM parameter store not fetching all key/values

Could someone let me know why the below code only fetching few entries from the parameter store ?
GetParametersByPathRequest getParametersByPathRequest = new GetParametersByPathRequest();
getParametersByPathRequest.withPath("/").setRecursive(true);
getParametersByPathRequest.setWithDecryption(true);
GetParametersByPathResult result = client.getParametersByPath(getParametersByPathRequest);
result.getParameters().forEach(parameter -> {
System.out.println(parameter.getName() + " - > " + parameter.getValue());
});

GetParametersByPath is a paged operation. After each call you must retrieve NextToken from the result object, and if it's not null and not empty you must make another call with it added to the request.
Here's an example using DescribeParameters, which has the same behavior:
DescribeParametersRequest request = new DescribeParametersRequest();
DescribeParametersResult response;
do
{
response = client.describeParameters(request);
for (ParameterMetadata param : response.getParameters())
{
// do something with metadata
}
request.setNextToken(response.getNextToken());
}
while ((response.getNextToken() != null) && ! respose.getNextToken.isEmpty());

Here is the code, based on the code above, for the new 2.0 version of AWS SSM manager. Notice I have set the maxResults to 1 to prove out the loop. You will want to remove that. AWS has mentioned that in the new code they wanted to emphasize immutability.
Using this dependency:
<dependency>
<groupId>software.amazon.awssdk</groupId>
<artifactId>ssm</artifactId>
<version>2.10.32</version>
</dependency>
I came up with this code:
private void refreshCache() {
StopWatch sw = StopWatch.createStarted();
GetParametersByPathRequest request = GetParametersByPathRequest.builder()
.path(prefix)
.withDecryption(useDecryption)
.maxResults(1)
.build();
GetParametersByPathResponse response;
do {
response = ssm.getParametersByPath(request);
for (Parameter p : response.parameters()) {
//do something with the values.
}
request = GetParametersByPathRequest.builder()
.path(prefix)
.withDecryption(useDecryption)
.nextToken(response.nextToken())
.maxResults(1)
.build();
}
while (StringUtils.isNotBlank(response.nextToken()));
LOG.trace("Refreshed parameters in {}ms", sw.getTime());
}

private void getSsmParams() {
AWSSimpleSystemsManagement client = AWSSimpleSystemsManagementClientBuilder.defaultClient();
GetParametersByPathRequest request = new GetParametersByPathRequest();
request.withRecursive(true);
request.withPath('/your/path/parameterName').setWithDecryption(true);
GetParametersByPathResult response;
do {
response = client.getParametersByPath(request);
for (Parameter p : response.parameters()) {
//do something with the values. maybe add to a list
}
request.setNextToken(response.getNextToken())
}
while (StringUtils.isNotBlank(response.getNextToken()));
}
Above piece of code worked for me .ssm only sends 10 parameters at a time, so if you want to fetch more than 10 parameters from ssm parameter store programatically you will have to use multiple calls to fetch them. here the token is important , if there are more values in the path (request.withPath('/your/path/parameterName')) you have given, it will send a token indicating that there are more values in the given path ,and you will have to make the following request with the token received from the previous request in order to get the rest of the values.

Passing phone input via Twilio

I'm working on a basic Twilio web application using Java and the Spark Java framework. I'm trying to have the user enter a number as input after the initial prompt through a Gather verb and then process that input. So far, I am able to call my Twilio number and it responds with the initial prompt, but after I enter a number it goes to /handle-number and crashes because the request did not contain any params and it can't find the "Digits" param (params is empty when I print it).
I have tried to mimic the API call via the Postman Chrome extension to debug it, but I get a 500 internal server error.
EDIT: Here is a screenshot of the postman request : Postman screenshot
I am new to Java web applications, HTTP requests, and Twilio, so I am unfamiliar with much of this. I have gone thought the twiml documentation and tutorials and tried to follow along but my I'm definitely missing something in my implementation.
How do I properly pass the phone input to the processNumber Route? Any help is appreciated!
App.java
import static spark.Spark.*;
public class App {
public static void main (String[] args){
post("/receive-call", ReceiveCall.call);
post("/handle-number", ReceiveCall.processNumber);
}
}
ReceiveCall.java
import com.twilio.twiml.voice.Gather;
import com.twilio.twiml.voice.Say;
import com.twilio.twiml.*;
import spark.Route;
public class ReceiveCall {
public static Route call = (request, response) -> {
Say sayMessage = new Say.Builder("Hello! Please enter a number as input. Enter # when finished.").build();
Gather input = new Gather.Builder().timeout(3).say(sayMessage).action("/handle-number").build();
VoiceResponse twiml = new VoiceResponse.Builder().gather(input).build();
System.out.println(response.body());
return twiml.toXml();
};
public static Route processNumber = ((request, response) -> {
String digit = request.params("Digits");
//CRASHES HERE BECAUSE digit IS NULL
int number = Integer.parseInt(digit);
Say message = process(number);
VoiceResponse twiml = new VoiceResponse.Builder().say(message).build();
return twiml.toXml();
});

The reason of "digit IS NULL" is: you are using request.params(...), which is for path parameter.
What is "path parameter"?
"path parameter" means passing parameter as part of URL path, especially in RESTful style request.
For example, if you want to send an HTTP GET request to retrieve a book by its ISBN, the request URL could be: /books/9787121022982 or /books/9787101054491, where the ISBN parameter is passed as part of URL path (9787121022982 and 9787101054491). In Spark framework, the corresponding Route code would be:
get("/books/:isbn", (request, response) -> {
return "Book ISBN is: " + request.params(":isbn");
});
What is "query parameter"?
"query parameter" means passing parameter as part of URL queries (entities after the ? character in URL).
Take the previous book ISBN case for example, if you want to pass ISBN as query parameter, the HTTP GET URL would be: /books?isbn=9787121022982, and the corresponding Spark Route code is:
get("/books", (request, response) -> {
return "Book ISBN is: " + request.queryParams("isbn");
});
What is the best practice to pass data in POST request?
In your case, the /handle-number route accept POST request. For HTTP POST request, it's not a good practice to pass data as parameter in URL. Instead, you need to pass data as request body, and get data from body in Spark code:
post("/handle-number", (request, response) -> {
String body = request.body();
// extract ISBN from request body string
});

Versioning REST APIs and vendor specific content type

I read a lot about versioning REST APIs, f.e. in this thread: Best practices for API versioning?
Because of that I would like to use the HTTP-Accept-Header to indicate which version the client is asking for.
But how can I apply this in my application? Which changes had therefore be made? How does the marshaller know, which version should be used? Do I have to register my type?
What I know is that I have to change the content of the #Produces-Annotation
#GET
#Path("/locations")
#Produces("application/vnd.mycompany-v1+xml")
Location[] getLocations();
But what else has to be changed?

You can use the Variant mechanisms of JAX-RS.
#GET
#Path("/locations/{id}")
#Produces(value = {"application/vnd.mycompany-v2+json", // current version
"application/vnd.mycompany-v1+json", // old version
MediaType.APPLICATION_JSON}) // fallback
public Response getLocation(#PathParam("id") Integer id,
#Context Request request) {
MediaType vndTypeV1 = new MediaType("application", "vnd.mycompany-v1+json");
MediaType vndTypeV2 = new MediaType("application", "vnd.mycompany-v2+json");
Variant variant1 = new Variant(vndTypeV1, null, null);
Variant variant2 = new Variant(vndTypeV2, null, null);
Variant variantJson = new Variant(MediaType.APPLICATION_JSON_TYPE, null, null);
List<Variant> variants = new ArrayList<Variant>();
variants.add(variant1);
variants.add(variant2);
variants.add(variantJson);
Variant selectedVariant = request.selectVariant(variants);
Location location = someBackendService.getLocation(id);
// Manipulate location according to which variant is the selectedVariant.
// ...
return Response.ok("{}")
.header(HttpHeaders.CONTENT_TYPE, selectedVariant.getMediaType())
.build();
}
See the Java EE 6 Tutorial, too.
Edit
There is no automatic way to marshal an entity according to the selected variant. This requires some manual work. For example:
String version = extractVersionFromVariant(selectedVariant);
if ("v1".equals(version)) {
location.setSomeV1Propery("only in v1);
} else if ("v2".equals(version)) {
location.setSomeV2Propery("only in v2);
}
return Response.ok(location)
.header(HttpHeaders.CONTENT_TYPE, selectVariant.getMediaType())
.build();
If the versions are different enough, I'd use a JAXB annotated class for each version. Each such class would then only contain those properties that are valid for this version. JAX-RS takes care to marshal them to JSON.

As far as I know you can't use JAX-RS to automatically route to different methods based on an http header.
You can read the header within you method (with #HeaderParam or HttpHeaders on the #context see here) and call the appropriate version

How do I access POST variables in my controller?

I am making the following AJAX request:
$.post('/route', {
arg1 : 'foo',
arg2 : 'bar'
});
Through the route:
POST /route controllers.Test.readPost()
How do I access these POST variables in the method of my controller?
public static Result readPost() {
return TODO; // read post variables
}
I cannot find a simple way of doing this in the documentation. It only states how to get values from JSON requests.

Use DynamicForm
public static Result getValues(){
DynamicForm requestData = form().bindFromRequest();
String name = requestData.get("name");
String desg = requestData.get("desg");
// etc
return ok("You sent: " + name + ", " + desg);
}
There is also other possibility to construct AJAX query and pass arguments via javascriptRoutes: https://stackoverflow.com/a/11133586/1066240
Of course it will pass the params via URL so it's not suitable for every value, but in many places it will be goot enough for sending POST requests with AJAX. Of course javascriptRoutes create the request with type set in routes file.
BTW: it was better if you wrote which version you are using.

you can use GET with an ajaxRequest. more information can be found here http://www.javascriptkit.com/dhtmltutors/ajaxgetpost.shtml
var mygetrequest=new ajaxRequest()
mygetrequest.onreadystatechange=function(){
if (mygetrequest.readyState==4){
if (mygetrequest.status==200 || window.location.href.indexOf("http")==-1){
document.getElementById("result").innerHTML=mygetrequest.responseText
}
else{
alert("An error has occured making the request")
}
}
}
var namevalue=encodeURIComponent(document.getElementById("name").value)
var agevalue=encodeURIComponent(document.getElementById("age").value)
mygetrequest.open("GET", "basicform.php?name="+namevalue+"&age="+agevalue, true)
mygetrequest.send(null)

In Java, how to set the header of a Restlet Response?

I can't seem to figure out how to add headers to my restlet response. When I look at the available methods in the Response object, all I see is setStatus, setEntity, and setAttributes but none of these tell me how to set custom http headers on the response.
For example, I have a GET call the returns something like the following:
HTTP/1.1 200 OK
Content-Type: text/json
Content-Length: 123
Some-Header: the value
Some-Other-Header: another value
{
id: 111,
value: "some value this could be anything",
diagnosis: {
start: 12552255,
end: 12552261,
key: "ABC123E11",
source: "S1",
}
}
Whatever it maybe. In the handleGet method, I handle it like so:
final MediaType textJsonType = new MediaType("text/json");
#Override
public void handleGet() {
log.debug("Handling GET...");
final Response res = this.getResponse();
try {
final MyObject doc = this.getObj("hello", 1, "ABC123E11", "S1");
final String docStr = doc.toString();
res.setStatus(Status.SUCCESS_OK);
res.setEntity(docStr, textJsonType);
// need to set Some-header, and Some-other-header here!
}
catch(Throwable t) {
res.setStatus(Status.SERVER_ERROR_INTERNAL);
res.setEntity(new TextRepresentation(t.toString()));
}
}

Because Restlet is more about the REST architectural principles than HTTP, it tries to be protocol agnostic and doesn't expose the HTTP headers directly. However, they are stored in the org.restlet.http.headers attribute of the response (as a Form). Note that you can only set custom headers this way, not standard ones (these are handled directly by the framework, e.g. Content-Type depends on the Representation's MediaType).
See this for an example:
http://blog.arc90.com/2008/09/15/custom-http-response-headers-with-restlet/ (link content also available from the Internet Archive Wayback Machine).