I'm sending series of texts to be classified by https://iab.taxonome.org classification API, but since I work in node JS enviroment in a proper, async way, the responses get's out of sync with the requests. I can use recorsive calls, but this might overflow my stack. Any idea how to sync calls with classification responses?
You might use the optional private ID to pass a "cookie" to identify the session.
From https://iab.taxonome.org/api
id optional String Request user defined identifier or empty string.
curl -i https://rest.taxonome.org/v1/taxono?me=this%20is%20a%20text%20to%20be%20classified&token=123e4567-e89b-12d3-a456-426655440000&ver=1&id=MyUserDefinedId
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I have a Node JS application running with Express and mongodb. I have a use case where my device sends data to my server. It might be JSON data or Comma-Separated String(Only String, not CSV file). I need to check which type of data is coming and manipulate that to JSON if request body would be a String. When I was trying to display the data type of data being sent to the server, it's displaying as "object" even after giving the "String" data as input. And the operation is getting successful but data is not inserting into the database. Can anyone help me in resolving this issue?
Sample Payload(request.body) would be,
"heat:22,humidity:36,deviceId:sb-0001"
Expected response is,
{
"heat": "22",
"humidity": "36",
"deviceId": "sb-0001"
}
#Aravind Actually typeof will returns "string" if operand is a string.So please check whether the string is coming or not in body, because if it is null then typeof will return "object".
I need to check which type of data is coming and manipulate that to JSON ...
HTTP is build upon the media-type concept that defines the syntax used in the payload of that type as well as the semantics of the elements used within that payload. You might take a look at how HTML defines forms to get a grip what a media-type specification should include. Through content negotiation client and server agree on a common media-type and thus a representation format to exchange payloads for supported by both. This simply increases interoperability between the participants as they exchange data in well-defined, hopefully standardized, representation formats both understand and support.
Through Accept headers a receiver can state preferences on which types to receive, including a weighting scheme to indicate that a certain representation format is preferred over an other one but the recipient is also fine with the other one, while a Content-Type header will indicate the actual representation format being sent.
RFC 7111 defines text/csv for CSV based representations and RFC 8259 specifies application/json for JSON payload. As the sender hopefully knows what kind of document it sends to the receiver, you can use this information to distinguish the payload on the receiver side. Note however that according to Fielding true REST APIs must use representation formats that support hypertext-driven interaction flows to allow clients to take further actions upon the payload received without having to invoke some external documentation. Both, JSON and CSV, by default don't support such an interaction model, that is abreviated with the term HATEOAS. For your simple scenario the content type negotiation might though be sufficient enough to solve your needs.
In terms of processing CSV and converting the data to JSON this is simply a matter of splitting up the CSV string on the delimiter symbol (, in the sample) to key-value pairs and then splitting the key and values further on the : symbol and adding these to a new JSON object. There is also a csvtojson library available at NPM that you might utilize in such a case.
I would like to do a DELETE request with unspecified number of parameters a=someValue. There is 2 main ways of supplying parameters to my understanding
Query parameters. ?a=someValue . This approach turn everything into
string and since I allow any number of parameters, I cannot know
which one is String, Boolean or Integer
Parameters in Body.This approach goes against the spec of DELETE operation to not have a body. Some server even strip away the body-content. But as I
send an json object, user can specify which type of value each of
their parameters has.
What would be your approach for this?
I'd use query parameters over body as the DELETE method has an optional body. Some clients may choose to ignore the body totally.
I have a scenario like this
User says: What's the temperature in SF?
bot executes: get_forecast
updates context with: forecast
bot send: {forecast}
Is there a way to use {forecast} and extract entities from it? For example, I can continue the above story as -
User say: convert that in celsius
<extract temperature from {forecast} set entities>
bot execute: convert_to_celsius
updates context with: temperature
bot sends: {temperature}
Any suggestions on how to do this?
The entity value can be stored in context, or on your backend/server.
If you store {forecast} in context, when user request conversion to celsius, you retrieve it from context, convert it and update context with {temperature}.
However, note that 'context' is passed around between user and your backend so I do not recommend putting too many unnecessary values in it, due to more data being transmitted for each call.
For your use case, you could storing {forecast} on your server instead. When user request conversion, simply retrieve it and update context.
Since, I can get parameters from both the methods using a code similar to the one below:
req.params.<PARAM NAME> in single/many separate app.METHOD function(s)
(think this may result in code repetition)
&
app.params(<ARRAY>,<CALLBACK>) function, independent of the app.METHOD functions, and called if the URL contains any parameter (:id, :name .etc)
What are the use-cases to apply one over the other?
My best guess would be is using app.params for parameter validation or some sort of preprocessing. For example the express docs provide and example where you attach req.user information to the request using app.params and after that you can work directly with the user information instead of processing the parameter again. Using req.params would be more specific in terms of processing the specific query. For example I'd use req.params for a REST endpoint which should perform an operation by id (update/delete) as in general there shouldn't be any additional preprocessing involder.
I'm writing a REST api in node js that will execute a sql query and send the results;
in the request I need to send the WHERE conditions; ex:
GET 127.0.0.1:5007/users //gets the list of users
GET 127.0.0.1:5007/users
id = 1 //gets the user with id 1
Right now the conditions are passed from the client to the rest api in the request's headers.
In the API I'm using sequelize, an ORM that needs to receive WHERE conditions in a particular form (an object); ex: having the condition:
(x=1 AND (y=2 OR z=3)) OR (x=3 AND y=1)
this needs to be formatted as a nested object:
-- x=1
-- AND -| -- y=2
| -- OR ----|
| -- z=3
-- OR -|
|
| -- x=3
-- AND -|
-- y=1
so the object would be:
Sequelize.or (
Sequelize.and (
{x=1},
Sequelize.or(
{y=2},
{z=3}
)
),
Sequelize.and (
{x=3},
{y=1}
)
)
Now I'm trying to pass a simple string (like "(x=1 AND (y=2 OR z=3)) OR (x=3 AND y=1)"), but then I will need a function on the server that can convert the string in the needed object (this method in my opinion has the advantage that the developer writing the client, can pass the where conditions in a simple way, like using sql, and this method is also indipendent from the used ORM, with no need to change the client if we need to change the server or use a different ORM);
The function to read and convert the conditions' string into an object is giving me headache (I'm trying to write one without success, so if you have some examples about how to do something like this...)
What I would like to get is a route capable of executing almost any kind of sql query and give the results:
now I have a different route for everything:
127.0.0.1:5007/users //to get all users
127.0.0.1:5007/users/1 //to get a single user
127.0.0.1:5007/lastusers //to get user registered in the last month
and so on for the other tables i need to query (one route for every kind of request I need in the client);
instead I would like to have only one route, something like:
127.0.0.1:5007/request
(when calling this route I will pass the table name and the conditions' string)
Do you think this solution would be a good solution or you generally use other ways to handle this kind of things?
Do you have any idea on how to write a function to convert the conditions' string into the desired object?
Any suggestion would be appreciated ;)
I would strongly advise you not to expose any part of your database model to your clients. Doing so means you can't change anything you expose without the risk of breaking the clients. One suggestion as far as what you've supplied is that you can and should use query parameters to cut down on the number of endpoints you've got.
GET /users //to get all users
GET /users?registeredInPastDays=30 //to get user registered in the last month
GET /users/1 //to get a single user
Obviously "registeredInPastDays" should be renamed to something less clumsy .. it's just an example.
As far as the conditions string, there ought to be plenty of parsers available online. The grammar looks very straightforward.
IMHO the main disadvantage of your solution is that you are creating just another API for quering data. Why create sthm from scratch if it is already created? You should use existing mature query API and focus on your business logic rather then inventing sthm new.
For example, you can take query syntax from Odata. Many people have been developing that standard for a long time. They have already considered different use cases and obstacles for query API.
Resources are located with a URI. You can use or mix three ways to address them:
Hierarchically with a sequence of path segments:
/users/john/posts/4711
Non hierarchically with query parameters:
/users/john/posts?minVotes=10&minViews=1000&tags=java
With matrix parameters which affect only one path segment:
/users;country=ukraine/posts
This is normally sufficient enough but it has limitations like the maximum length. In your case a problem is that you can't easily describe and and or conjunctions with query parameters. But you can use a custom or standard query syntax. For instance if you want to find all cars or vehicles from Ford except the Capri with a price between $10000 and $20000 Google uses the search parameter
q=cars+OR+vehicles+%22ford%22+-capri+%2410000..%2420000
(the %22 is a escaped ", the %24 a escaped $).
If this does not work for your case and you want to pass data outside of the URI the format is just a matter of your taste. Adding a custom header like X-Filter may be a valid approach. I would tend to use a POST. Although you just want to query data this is still RESTful if you treat your request as the creation of a search result resource:
POST /search HTTP/1.1
your query-data
Your server should return the newly created resource in the Location header:
HTTP/1.1 201 Created
Location: /search/3
The result can still be cached and you can bookmark it or send the link. The downside is that you need an additional POST.