How to define complex routes with named parameters in express.js? - express

I want to set up some more complex routes that can include a number of optional parameters. Preferably, I would like to use named parameters for ease of access. Here is an example of what I'm trying to achieve:
// The following routes should be matched based on parameters provided:
// GET /books/:category/:author
// GET /books/:category/:author/limit/:limit
// GET /books/:category/:author/skip/:skip
// GET /books/:category/:author/limit/:limit/skip/:skip
// GET /books/:category/:author/sort/:sortby
// GET /books/:category/:author/sort/:sortby/limit/:limit
// GET /books/:category/:author/sort/:sortby/skip/:skip
// GET /books/:category/:author/sort/:sortby/limit/:limit/skip/:skip
app.get('/books/:category/:author/(sort/:sortby)?/(limit/:limit)?/(skip/:skip)?', myController.index);
As you can see, I'm trying to group the optional parameters with (paramKey/paramValue)?. That way I was hoping to be able to "mix and match" the optional parameters while still making use of the parameter naming. Unfortunately, this doesn't seem to work.
Is there any way to get this working without having to write straight regular expressions and adding additional logic to parse any resulting index-based parameter groups?
Basically, I'm looking for an easy way to parse key/value pairs from the route.

It looks like you want to re-implement the query string using the URL path. My guess is that if you really wanted that, yes, you would have to write your own parsing/interpreting logic. AFAIK express path parameters are positional, whereas the query string is not. Just use a query string and express will parse it for you automatically.
/books?category=sports&author=jack&limit=15?sortby=title
That will enable you to do
req.query.sortby
You may be able to get express to do 1/2 of the parsing for you with a regular expression path like (:key/:value)* or something along those lines (that will match multiple key/value pairs), but express isn't going to then further parse those results for you.

you can send data to view as follow:
//in the server side ...
app.get('/search/:qkey/:qvalue', function(req, res){
res.write(JSON.stringify({
qkey:req.params.qkey;
qvalue:req.params.qvalue;
}));
});
and in the client side... call to ajax
$.ajax({
type:"POST",
url:"/search/"+qkey+"/"+qvalue,
success: function(data){
var string = eval("(" + data + ")");
//you access to server response with
console.log(string.qkey+" and "+ string.qvalue);
}
});

Related

How to access values from list of maps in Apache camel message body

Perhaps this is easy, but I am somehow not able to crack it yet. Message body for an exchange is basically a list of maps with both key & value being string. As example,
[{'key'='val1'}, {'key'='val2'},...]
I am using simple expression to set this as a property which I would be using in subsequent routes. This is how I am setting it:
.setProperty("myProperty", simple("${body}"))
But this sets the complete body. I just want to (somehow) set only the values part to avoid setting the entire list of maps. What I have tried and not working so far:
.setProperty("myProperty", simple("${body}['key']"))
.setProperty("myProperty", simple("${body}[*]['key']"))
.setProperty("myProperty", simple("${body}[0]['key']")) // this returns only the first value, I want all
Any idea/suggestion how can I achieve this ?
You can access every level of your body with Simple expressions:
${body} // get whole list of maps
${body[0]} // get first map in the list (index 0)
${body[0][key]} // get value of key "key" from the first map in the list
What you cannot do in a Simple expression is a conversion of your data structure in another one.
However, you can simply plug a Java bean into your route
from("direct:start")
...
.bean(MyConversionBean.class)
...;
And do the conversion with Java
public class MyConversionBean {
public List<String> convertBody() {
// extract all values (or whatever) with Java;
return listOfValues;
}
}

Api Platform pagination custom page_parameter_name

I have very specific question on which I cannot find any answer and/or solution provided for Api Platform.
By default, the documentation states, that if you want to pass a page parameter for paging action, you must do the following:
pagination:
page_parameter_name: _page
However, due to the nature of our frontend we're not able to pass this variable to the request. It is hardcoded to the frontend request and is something like page[number]=1.
Is it possible to configure page_parameter_name to receive this variable or we need to transform it somehow in the Api itself?
Thank you!
ApiPlatform\Core\EventListener\ReadListener::onKernelRequest gets $context['filters'] from the request through ApiPlatform\Core\Util\RequestParser::parseRequestParams which ultimately uses PHP's parse_str function so the value of 'page[number]' will be in $context$context['filters']['page']['number'].
ApiPlatform\Core\DataProvider\Pagination::getPage retrieves the page number from $context['filters'][$parameterName] so whatever the value of [$parameterName] it will at best retrieve the array ['number'=> 1].
Then ::getPage casts that to int, which happens to be 1. But will (at least with PHP7) be 1 for any value under 'number'.
Conclusion: You need to transform it somehow in the Api itself. For example by decoration of the ApiPlatform\Core\DataProvider\Pagination service (api_platform.pagination).
API_URL?page[number]=2
print_r($request->attributes->get('_api_pagination'));
Array(
[number] => 2
)
The value of the "page_parameter_name" parameter should be "number" .
api_platform.yaml
collection:
pagination:
page_parameter_name: number
This may not work in version 3
vendor/api-platform/core/src/JsonApi/EventListener/TransformPaginationParametersListener.php
public function onKernelRequest(RequestEvent $event): void
{
$request = $event->getRequest();
$pageParameter = $request->query->all()['page'] ?? null;
...
/* #TODO remove the `_api_pagination` attribute in 3.0 */
$request->attributes->set('_api_pagination', $pageParameter);
}

Why does GraphQL query work with the "query" keyword before the curly braces?

I created a small API for authors and books as example. The problem is that I don't understand why a query can look different but still get me the same output. I've included 3 examples.
The GraphQL query looks like this:
{
"query":
"query{
author(id: 1) {
name
}
}"
}
Why is this query working if within the query is the keyword "query" two times? When I write the query like this:
{
"query":
"{
author(id: 1) {
name
}
}"
}
it also works, and when I write it like that:
{
"query":
"author{
author(id: 1) {
name
}
}"
}
It is not working. Why is that so?
GraphQL specifies three types of operations:
query – a read‐only fetch.
mutation – a write followed by a fetch.
subscription – a long‐lived request that fetches data in response to source events.
What you are sending to your server is a JSON object with a single property (query) the value of which is a GraphQL document that represents your actual request to the GraphQL service. This property is (unfortunately) called query by convention but it has nothing to do with the actual operation inside the document you are sending.
Any operation included in your GraphQL document must follow this format:
OperationType [Name] [VariableDefinitions] [Directives] SelectionSet
Name, VariableDefinitions and Directives are all optional. The OperationType is one of query, mutation or subscription. SelectionSet is the collection of fields you are requesting for that operation type. Only selection sets are wrapped in curly brackets. In your example, you have two selection sets -- one containing the author field and one containing the name field.
There's an exception to the above called query shorthand:
If a document contains only one query operation, and that query defines no variables and contains no directives, that operation may be represented in a short‐hand form which omits the query keyword and query name.
In other words if your operation:
is a query
is the only operation in the document
contains no variable definitions or directives
You can omit the query keyword and the operation name. This leaves you with just a selection set, which is wrapped in a set of curly brackets.
So your first two examples are equally valid. The third example is not valid because author is not a valid operation kind.
The first query key on your examples is a requirement from GraphQL to actually call the endpoint, it has to be present to actually run queries or mutations. You can see it in the docs.
The first example works because at the root of a GraphQL Schema there has to be an action with keywords query or mutation, and in your case you are triggering a query.
The second example works because if you don't define what type of action (query or mutation) on your request, it always defaults to execute a query.
The third example does not work because you don't have the action author at the root of your Schema.
I guess the first keyword query is what makes some confusion in this case.

RxJS Is there a way to make ajax get request with params without building url

I am having trouble passing params to ajax get request.
Let's suppose i have to pass params {category: 'cat', type: 'type', searchKey: 'key' } to the url /search and I have the code below:
action$.ofType('QUERY')
.debounceTime(500)
.switchMap(action =>
ajax.get('/search', {//pass some parameters},)
.map(result => ({
type: 'FETCH_SUCCESS',
payload: result.response,
})),
As I am new to RxJs, Please suggest me the right way of doing this.
While it is technically permissible to provide a request body (and corresponding Content-Type header like application/x-www-form-urlencoded) for GET requests, nearly all servers assume GET do not contain one. Instead, POST (creation of a document) or PUT (updating a document) is used when a body is neccesary.
However, if what you're asking for is simply regular old query params, that's pretty normal but there is no built-in support in RxJS for converting an Object to a query string--mostly because there is no official spec on how complex objects/arrays should be serialized so every server has notable differences once you do more than simple key -> value.
Instead, you just include them in the URL. I realize you said "without building url" but the lack of a spec means RxJS will likely never add support because it's highly opinionated. You can just manually generate the string yourself or use a third-party utility that has a convention you like.
ajax.get(`/search?query=${query}&something=${something`)
// or using something like https://www.npmjs.com/package/query-string
ajax.get(`/search?${queryString.stringify(params)}`)
If you're interested in further understanding the opinionated nature of query params, consider how you might serialize { foo: [{ bar: 1 }, { bar: 2 }] }. Some might say it should be ?foo[0][bar]=1&foo[1][bar]=2 but I have also seen ?foo[][bar]=1&foo[][bar]=2, ?foo[bar]=1&foo[bar]=2, and other variants. Thing get even more hairy when dealing with duplicates. ?foo=true&foo=false should foo be true or false? (it's an opinion hehe)

Express routes parameters

I am trying to create two routes in my express app. One route, without a parameter will give me a list of choices, the other one with a parameter will give me the choice related to the id.
router.get('/api/choice', choice_controller.get_choices);
router.get('/api/choice/:id', choice_controller.get_choice);
When I go to .../api/choice/?id=1 the api returns the list of choices, and therefore follows the route without the param (/api/choice). How do I make sure that the router does not omit the parameter?
Thanks in advance.
UPDATE
It seems that it does not fire the /api/choice/:id route. If I remove the one without the param, it gives a 404 so. Could someone explain to me why /api/choice/?id=1 is not getting picked up by /api/choice/:id?
Basically, your declared routes are documented in the Express documentation.
The second route is resolved by a URL like /api/choice/hello where 'hello' is mapped into the req object object as:
router.get('/api/choice/:id', function (req, res) {
console.log("choice id is " + req.params.id);
});
What you are actually trying is mapping query parameters.
A URL like /api/choice/?id=1 is resolved by the first router you provided.
Query parameters are easy to get mapped against the request as:
router.get('/api/choice', function (req, res) {
console.log('id: ' + req.query.id);
//get the whole query as!
const queryStuff = JSON.stringify(req.query);
console.log(queryStuff)
});