I’m trying to pass a JSON object to Enyo using a web server.
The file being loaded from the service in Enyo:
{ "Comments" : ["NewComment 1", "NewComment 2", "NewComment 3" ]}
The following callback for the service generates an error saying
gotComments: function(inSender, inResponse) {
this.serverReply = InResponse; // error uncaught reference error: inResponse not defined
this.$.list.render();
},
When I click on inReply on my chrome debugger it says
Object:
Comments: Array[3]
How can it say it is not define, if the watch window shows it as
Object:
Comments: Array[3]
The code in your question mixes InResponse (capital I) and inResponse (lowercase i). Assuming this is what your real code looks like, change
this.serverReply = InResponse;
to
this.serverReply = inResponse;
Related
I have been trying for a few days to get a parameter sent from the API Gateway in AWS to a Lambda function and I am having no success.
I decided to start from the beginning so I followed their walkthrough (http://docs.aws.amazon.com/apigateway/latest/developerguide/getting-started.html#getting-started-new-lambda)
I have checked this walkthrough twice and I have followed the steps to the letter.
Problem
When I test the API from Postman or in Swift I am getting the error:
{"message": "Could not parse request body into json: Unexpected character (\'-\' (code 45)) in numeric value: expected digit (0-9) to follow minus sign, for valid numeric value\n at [Source: [B#c036d15; line: 1, column: 3]"}
In postman, When I view the result as JSON I just get
Bad String
Lambda Function
The function is the basic example from the Walkthrough:
console.log('Loading event');
exports.handler = function(event, context) {
var name = (event.name === undefined ? 'No-Name' : event.name);
console.log('"Hello":"' + name + '"');
context.done(null, {"Hello":name}); // SUCCESS with message
};
When Tested from the Lambda Console and with the Test data I get the result:
{
"Hello": "TestUser123"
}
When Tested from the API Gateway Test, The result is also:
{
"Hello": "TestUser123"
}
Can anyone see why both test consoles are allowing this work but when tested with POSTMAN or used within a Swift Script it does not work ?
Edit 1
In postman, I have set the content-type to application/json
The script returns the default:
{
"Hello": "user"
}
However, When I add in the parameters name and TestUser123 in POSTMAN, this is when it returns the error.
Update 1
Ok, so I changed the mapping template to one that I found on another answer:
{ "name": "$input.params('name')" }
Now the result is:
{
"Hello": ""
}
Any Ideas why it is not getting the name?
I just got stuck with this today.
your mapping template is:
{ "name": "$input.params('name')" }
AWS uses AWS Velocity templates, which; even though looks like JSON, is different.
if you use
{ "name": $input.params('name') } // notice no quotes
for the mapping template right at the integration request step, then it should work as expected.
Read the error message very carefully, it actually tells you the problem. For example, I got
Could not parse request body into json: Unexpected character (\'\"\' (code 34)): was expecting comma to separate Object entries
So the problem is that I'm missing a comma. I check my Lambda's Integration Request - Body Mapping Template:
{
"age" : $input.json('$.persondata.age'),
"income" : $input.json('$.persondata.income')
"height" : $input.json('$.persondata.height')
}
Can you spot the problem? I am missing a comma after the income line.
Here is another example.
Could not parse request body into json: Unexpected character (\'}\' (code 125)): expected a value
When I look at the Integration Request - Body Mapping Template:
#set($inputRoot = $input.path('$'))
{
"age" : $inputRoot.age,
"height" : $inputRoot.height,
"income" : $inputRootincome
}
Can you spot the problem? I am missing a dot in $inputRootincome.
Error Message :
Could not parse request body into json: Could not parse payload into json: Unrecognized token \' \': was expecting (\'true\', \'false\' or \'null\')
Cause of the error : When string values inside the json are not assigned using double quotations in the aws mapping template the error occurs.
Solution : (Please Note : This example is for application/json type request template)
Actually the solution for the problem is, if you are using a value of type string in json then its value should be assigned inside a ("" - double quotation marks) in the mapping template.
The below shown example has the following attributes :
customerId - string (Please note : this value comes from a query parameter)
customerName - string
customerAge - integer
isPermanentEmployee - boolean
customerAddress - string (Please note this is an optional parameter)
And the mapping template should be defined like the example shown below
Refer the example below :
#set($inputRoot = $input.path('$'))
{
"CustomerId": "$input.params('customerId')",
"CustomerName": "$inputRoot.customerName",
"CustomerAge": $inputRoot.customerAge,
"IsPermanentEmployee": $inputRoot.isPermanentEmployee
"CustomerAddress ": #if($inputRoot.customerAddress == "") "" #elseif($inputRoot.customerAddress != "") "$inputRoot.customerAddress" #end
}
If you note the above mapping template, I would have given string values inside double quotation marks("") which will solve the error
Also this example contains how to handle optional parameters in aws mapping templates using #if#else statements.
It is likely that you had copy-pasted multiple lines in your "Integration Request" in the API gateway.
When copying a line and pasting it below, you might have copied the hidden character '\n' at the end of that line. This is probably causing issues at the lambda function.
Example: Copying the line containing age and pasting it twice and modifying them to have height and income respectively.
#set($inputRoot = $input.path('$'))
{
"age" : $inputRoot.age,
"height": $inputRoot.height,
"income": $inputRoot.income
}
Instead of copy-pasting, just type the line out for height and income.
Using Elm's html package it is possible to make http requests:
https://api.github.com/users/nytimes/repos
These are all the New York Times repos on Github. Basically there are two items I'd want from the Github response, the id and name
[ { "id": 5803599, "name": "backbone.stickit" , ... },
{ "id": 21172032, "name": "collectd-rabbitmq" , ... },
{ "id": 698445, "name": "document-viewer" , ... }, ... ]
The Elm type for Http.get requires a Json Decoder object
> Http.get
<function> : Json.Decode.Decoder a -> String -> Task.Task Http.Error a
I don't know how to open lists yet. So I put the decoder Json.Decode.string and at least the types matched, but I had no idea what to do with the task object.
> tsk = Http.get (Json.Decode.list Json.Decode.string) url
{ tag = "AndThen", task = { tag = "Catch", task = { tag = "Async", asyncFunction = <function> }, callback = <function> }, callback = <function> }
: Task.Task Http.Error (List String)
> Task.toResult tsk
{ tag = "Catch", task = { tag = "AndThen", task = { tag = "AndThen", task = { tag = "Catch", task = { tag = "Async", asyncFunction = <function> }, callback = <function> }, callback = <function> }, callback = <function> }, callback = <function> }
: Task.Task a (Result.Result Http.Error (List String))
I just want an Elm object of the repo names so I can display in some div elements, but I can't even get the data out.
Can someone slowly walk me through how to write the decoder and how to get the data out with Elm?
Update for Elm 0.17:
I have updated the complete gist of this answer to work with Elm 0.17. You can see the full source code here. It will run on http://elm-lang.org/try.
A number of language and API changes were made in 0.17 that make some of the following recommendations obsolete. You can read about the 0.17 upgrade plan here.
I will leave the original answer for 0.16 untouched below, but you can compare the final gists to see a list of what has changed. I believe the newer 0.17 version is cleaner and easier to understand.
Original Answer for Elm 0.16:
It looks like you're using the Elm REPL. As noted here, you're not going to be able to execute tasks in the REPL. We'll get to more on why in a bit. Instead, let's create an actual Elm project.
I'm assuming you've downloaded the standard Elm tools.
You'll first need to create a project folder and open it up in a terminal.
A common way to get started on an Elm project is to use the StartApp. Let's use that as a starting point. You first need to use the Elm package manager command line tool to install the required packages. Run the following in a terminal in your project root:
elm package install -y evancz/elm-html
elm package install -y evancz/elm-effects
elm package install -y evancz/elm-http
elm package install -y evancz/start-app
Now, create a file at the project root called Main.elm. Here is some boilerplate StartApp code to get you started. I won't go into explaining the details here since this question is specifically about Tasks. You can learn more by going through the Elm Architecture Tutorial. For now, copy this into Main.elm.
import Html exposing (..)
import Html.Events exposing (..)
import Html.Attributes exposing (..)
import Html.Attributes exposing (..)
import Http
import StartApp
import Task exposing (Task)
import Effects exposing (Effects, Never)
import Json.Decode as Json exposing ((:=))
type Action
= NoOp
type alias Model =
{ message : String }
app = StartApp.start
{ init = init
, update = update
, view = view
, inputs = [ ]
}
main = app.html
port tasks : Signal (Task.Task Effects.Never ())
port tasks = app.tasks
init =
({ message = "Hello, Elm!" }, Effects.none)
update action model =
case action of
NoOp ->
(model, Effects.none)
view : Signal.Address Action -> Model -> Html
view address model =
div []
[ div [] [ text model.message ]
]
You can now run this code using elm-reactor. Go to the terminal in your project folder and enter
elm reactor
This will run a web server on port 8000 by default, and you can pull up http://localhost:8000 in your browser, then navigate to Main.elm to see the "Hello, Elm" example.
The end goal here is to create a button which, when clicked, pulls in the list of nytimes repositories and lists the IDs and names of each. Let's first create that button. We'll do so by using the standard html generation functions. Update the view function with something like this:
view address model =
div []
[ div [] [ text model.message ]
, button [] [ text "Click to load nytimes repositories" ]
]
On its own, the button click does nothing. We need to create an Action that is then handled by the update function. The action the button is initiating is to fetch data from the Github endpoint. Action now becomes:
type Action
= NoOp
| FetchData
And we can now stub out the handling of this action in the update function like so. For now, let's change the message to show that the button click was handled:
update action model =
case action of
NoOp ->
(model, Effects.none)
FetchData ->
({ model | message = "Initiating data fetch!" }, Effects.none)
Lastly, we have to cause button clicks to trigger that new action. This is done using the onClick function, which generates a click event handler for that button. The button html generation line now looks like this:
button [ onClick address FetchData ] [ text "Click to load nytimes repositories" ]
Great! Now the message should be updated when you click it. Let's move onto Tasks.
As I mentioned earlier, the REPL does not (yet) support the invoking of tasks. This may seem counterintuitive if you're coming from an imperative language like Javascript, where when you write code that says "go fetch data from this url," it immediately creates an HTTP request. In a purely functional language like Elm, you do things a little differently. When you create a Task in Elm, you're really just indicating your intentions, creating a sort of "package" that you can hand off to the runtime in order to do something that causes side effects; in this case, contact the outside world and pull data down from a URL.
Let's go ahead and create a task that fetches the data from the url. First, we're going to need a type inside Elm to represent the shape of the data we care about. You indicated that you just wanted the id and name fields.
type alias RepoInfo =
{ id : Int
, name : String
}
As a note about type construction inside Elm, let's stop for a minute and talk about how we create RepoInfo instances. Since there are two fields, you can construct a RepoInfo in one of two ways. The following two statements are equivalent:
-- This creates a record using record syntax construction
{ id = 123, name = "example" }
-- This creates an equivalent record using RepoInfo as a constructor with two args
RepoInfo 123 "example"
That second was of constructing the instance will become more important when we talk about Json decoding.
Let's also add a list of these to the model. We'll have to change the init function as well to start off with an empty list.
type alias Model =
{ message : String
, repos : List RepoInfo
}
init =
let
model =
{ message = "Hello, Elm!"
, repos = []
}
in
(model, Effects.none)
Since the data from the URL comes back in JSON format, We'll need a Json Decoder to translate the raw JSON into our type-safe Elm class. Create the following decoder.
repoInfoDecoder : Json.Decoder RepoInfo
repoInfoDecoder =
Json.object2
RepoInfo
("id" := Json.int)
("name" := Json.string)
Let's pick that apart. A decoder is what maps the raw JSON to the shape of the type to which we're mapping. In this case, our type is a simple record alias with two fields. Remember that I mentioned a few steps ago that we can create a RepoInfo instance by using RepoInfo as a function that takes two parameters? That's why we're using Json.object2 to create the decoder. The first arg to object is a function that takes two arguments itself, and that's why we're passing in RepoInfo. It is equivalent to a function with arity two.
The remaining arguments spell out the shape of the type. Since our RepoInfo model lists id first and name second, that's the order in which the decoder expects the arguments to be.
We'll need another decoder to decode a list of RepoInfo instances.
repoInfoListDecoder : Json.Decoder (List RepoInfo)
repoInfoListDecoder =
Json.list repoInfoDecoder
Now that we have a model and decoder, we can create a function that returns the task for fetching the data. Remember, this isn't actually fetching any data, it's merely creating a function which we can hand off to the runtime later.
fetchData : Task Http.Error (List RepoInfo)
fetchData =
Http.get repoInfoListDecoder "https://api.github.com/users/nytimes/repos"
There are a number of ways of handling the variety of errors that can occur. Let's choose Task.toResult, which maps the result of the request to a Result type. It will make things easier on us in a bit, and is sufficient for this example. Let's change that fetchData signature to this:
fetchData : Task x (Result Http.Error (List RepoInfo))
fetchData =
Http.get repoInfoListDecoder "https://api.github.com/users/nytimes/repos"
|> Task.toResult
Note that I'm using x in my type annotation for the error value of Task. That's just because, by mapping to a Result, I'll never have to care about an error from the task.
Now, we're going to need some actions to handle the two possible results: An HTTP error or a successful result. Update Action with this:
type Action
= NoOp
| FetchData
| ErrorOccurred String
| DataFetched (List RepoInfo)
Your update function should now set those values on the model.
update action model =
case action of
NoOp ->
(model, Effects.none)
FetchData ->
({ model | message = "Initiating data fetch!" }, Effects.none)
ErrorOccurred errorMessage ->
({ model | message = "Oops! An error occurred: " ++ errorMessage }, Effects.none)
DataFetched repos ->
({ model | repos = repos, message = "The data has been fetched!" }, Effects.none)
Now, we need a way to map the Result task to one of these new actions. Since I don't want to get bogged down in error handling, I'm just going to use toString to change the error object into a string for debugging purposes
httpResultToAction : Result Http.Error (List RepoInfo) -> Action
httpResultToAction result =
case result of
Ok repos ->
DataFetched repos
Err err ->
ErrorOccurred (toString err)
That gives us a way to map a never-failing task to an Action. However, StartApp deals with Effects, which is a thin layer over Tasks (as well as a few other things). We'll need one more piece before we can tie it all together, and that's a way to map the never-failing HTTP task to an Effects of our type Action.
fetchDataAsEffects : Effects Action
fetchDataAsEffects =
fetchData
|> Task.map httpResultToAction
|> Effects.task
You may have noticed I called this thing, "never failing." That was confusing to me at first so let me try to explain. When we create a task, we're guaranteed a result, but it a success or failure. In order to make Elm apps as robust as possible, we in essence remove the possibility of failure (by which I mainly mean, an unhandled Javascript exception), by explicitly handling every case. That's why we've gone through the trouble of mapping first to a Result and then to our Action, which explicitly handles error messages. To say it never fails is not to say that HTTP problems can't happen, it's to say that we're handling every possible outcome, and errors are mapped to "successes" by mapping them to a valid action.
Before our final step, let's make sure our view can show the list of repositories.
view : Signal.Address Action -> Model -> Html
view address model =
let
showRepo repo =
li []
[ text ("Repository ID: " ++ (toString repo.id) ++ "; ")
, text ("Repository Name: " ++ repo.name)
]
in
div []
[ div [] [ text model.message ]
, button [ onClick address FetchData ] [ text "Click to load nytimes repositories" ]
, ul [] (List.map showRepo model.repos)
]
Lastly, the piece that ties this all together is to make the FetchData case of our update function return the Effect which initiates our task. Update the case statement like this:
FetchData ->
({ model | message = "Initiating data fetch!" }, fetchDataAsEffects)
That's it! You can now run elm reactor and click the button to fetch the list of repositories. If you want to test out the error handling, you can just mangle the URL for the Http.get request to see what happens.
I've posted the entire working example of this as a gist. If you don't want to run it locally, you can see the final result by pasting that code into http://elm-lang.org/try.
I've tried to be very explicit and concise about each step along the way. In a typical Elm app, a lot of these steps will be condensed down to a few lines, and more idiomatic shorthand will be used. I've tried to spare you those hurdles by making things as small and explicit as possible. I hope this helps!
I've read other posts that have similar 404 errors, my problem is that I can correctly query the JSON data, but can't save without getting this error.
I'm using Angular's $resource to interact with a JSON endpoint. I have the resource object returning from a factory as follows:
app.factory('Product', function($resource) {
return $resource('api/products.json', { id: '#id' });
});
My JSON is valid and I can successfully use resource's query() method to return the objects inside of my directive, like this:
var item = Product.query().$promise.then(function(promise) {
console.log(promise) // successfully returns JSON objects
});
However, when I try to save an item that I've updated, using the save() method, I get a 404 Not Found error.
This is the error that I get:
http://localhost:3000/api/products.json/12-34 404 (Not Found)
I know that my file path is correct, because I can return the items to update the view. Why am I getting this error and how can I save an item?
Here is my data structure:
[
{
"id": "12-34",
"name": "Greece",
"path": "/images/athens.png",
"description": ""
},
...
]
By default the $save method use the POST verb, you will need to figure out which HTTP verbs are accepted by your server en order to make an update, most modern api servers accept PATCH or PUT requests for updating data rather than POST.
Then configure your $resource instance to use the proper verb like this :
app.factory('Product', function($resource) {
return $resource('api/products.json', { id: '#id' }, {'update': { method:'PUT' }});
});
check $resource docs for more info.
NOTE: $resource is meant to connect a frontend with a backend server supporting RESTful protocol, unless you are using one to receive data & save it into a file rather than a db.
Otherwise if you are only working with frontend solution where you need to implement $resource and have no server for the moment, then use a fake one, there is many great solutions out there like deployd.
You probably don't implement POST method for urls like /api/products.json/12-34. POST method is requested from angular for saving a new resource. So you need to update your server side application to support it and do the actual saving.
app.factory('Product', function($resource) {
return $resource('api/products.json/:id', { id: '#id' });
});
Try adding "/:id" at the end of the URL string.
I have a JSON store that load data from a PHP script. This script call a Web Service and sometimes it get some errors and I need to capture them and show them in my app.
In my script I print this line when I get an error:
echo '{"success": "false", "error": "'.$res->state->Description.'"}';
In my app I have this code to load the store
targheStore.load({
params: { targa: searchForm.getValues().targa },
callback: function(records, operation, success) {
Ext.getBody().dom.style.cursor = "default";
if(!success){
$("#message2").slideDown('fast');
setTimeout(function() {
$("#message2").slideUp('medium')
}, 2700);
}
}
});
The jQuery code is to show a message "No record found" from the top, but I want to show the error message that I receive from json.
Inside of the operation argument is a request and response object. Use the response object as you would any Ajax response should allow you to handle your messages the way you'd like.
I suggest declaring a globally available handler for processing operation to look for JSON.parse(response.responseText).hasOwnProperty("error") and doing your custom operation in that way.
If you're not using JSONP for communication you can stuff your message in the raw text returned from an HTTP error code (400+) and the {error:} handler in your ajax would be the best way to route errors.
I am using struts 2 and velocity templates to generate JSON response.
Now the catch is the response is not generated using some velocity JSON plugin
it's just a String that comes out once velocity is done with its parsing and rendering of
response, and on client side I do eval to get the response from string to JSON.
What I really need is some solution on velocity's or struts' side where, once the result is
generated by velocity, the framework should call my API where I can convert the response output of vm file into JSON using my own logic. How do achieve this?
For example:
On browser using JavaScript I have designed a tree widget that I use for displaying comments in tree structure.
Say user clicks on comments button.
My UI widget will fire an AJAX to get data for comments.
This request is intercepted by STRUTS 2 framework.
It will call, say, getComments() action API and will populate an arrayList with comment object say cmt.
Now the response is handled by a velocity template(*.vm).
Now in vm I am writing code like this:
{ "CommentsData" : [
#set($sep="")
#foreach($c in $cmt)
$sep
{
"commentText" : $c.getText()
}
#set($sep=",")
#end
}
Now the final response may turn out like this:
{ "CommentsData" : [
{
"commentText" : "This is comment 1"
},
{
"commentText" : "This is comment 2"
},
{
"commentText" : "This is comment 3"
},
{
"commentText" : "This is comment 4"
}`
]
}
Now this may look like JSON, but its not strict JSON; I mean if I miss
some , somewhere then on client side in JavaScript my eval might fail or JSON.parse()
will fail, but on velocity template I have now clue if JSON is malformed.
So once the above velocity template is generated I need some control, where I can write some Java code to do some validations on the response.
I see that my approach to use velocity template to generate JSON output (actully a String that looks like JSON) may be wrong. But still I need to handle the response of every velocity template I have written.
Not sure how you are using velocity. We don't use velocity when outputting JSON; we just create a JSON convertible object and output it directly from controllers using response.write(jsonObject.toJson()). This way, proper JSON is always generated.