We are currently using visjs version 3 to map the dependencies of our custom built workflow engine. This has been WONDERFUL because it helps us to visualize the flow and find invalid or missing dependencies. What we want to do next is simplify the process of building the dependencies using the visjs manipulation feature. The idea would be that we would display a large group of nodes and allow the user to order them correctly. We then want to be able to submit that json structure back to the server for processing.
Would this be possible?
Yes, this is possible.
Vis.js dispatches various events that relate to user interactions with graph (e.g. manipulations, or position changes) for which you can add handlers that modify or store the data on change. If you use DataSets to store nodes and edges in your network, you can always use the DataSets' get() function to retrieve all elements in you handler in JSON format. Then in your handler, just use an ajax request to transmit the JSON to your server to store the entire graph in your DB or by saving the JSON as a file.
The oppposite for loading the graph: simply query the JSON from your server and inject it into the node and edge DataSets' using the set method.
You can also store the networks current options using the network's getOptions method, which returns all applied options as json.
Related
With the Copy Data transformation it is possible to retrieve data from a REST call (array with flat json objects, similar to Odata) and copy the contents to a flat table keeping the data types from the source but without the necessity to set the schema for that specific data.
When I try to recreate this with Data Flow, I can't get this to work. When I check the Data Preview of my Source I get a hierarchy with a body (with my odata like data) and a header. And if I send that to my sink (Avro) it will be saved in this same hierarchical structure (including the header). I know I can fix this manually by using a Select operation (body.column1, body.column2, etc.), but I want to make my Data Flow dynamic so I'm able to use it with multiple tables/endpoints.
So I receive it like this with my REST source:
link
And I want it to be like this at my Sink without hardcoding my schema:
link
The only work around I can come up with is retrieving the data using Copy Data, put it somewhere temporarily and then use my data flow to further transform the data. Is there a more easy way to do this? I cannot imagine that I'm the only one that has this issue.
Hopefully it's clear and somebody is able to help. Thank you very much in advance.
Data flow projection will get schema from API including body and header. Hence, when you use auto mapping everything going to be saved.
Below work arounds you can think of,
As you mentioned, using copy data first and then data flow to further transform.
Use select or derived column transformations and transform your data to get all column names and then finally use sink. For this you can opt with Column pattern matching syntax. So that one condition can be meet with multiple columns to transform.
Check below link to know about column pattern mappings.
https://learn.microsoft.com/en-us/azure/data-factory/concepts-data-flow-column-pattern
Is it possible to create a H2OFrame using the H2O's REST API and if so how?
My main objective is to utilize models stored inside H2O so as to make predictions on external H2OFrames.
I need to be able to generate those H2OFrames externally from JSON (I suppose by calling an endpoint)
I read the API documentation but couldn't find any clear explanation.
I believe that the closest endpoints are
/3/CreateFrame which creates random data and /3/ParseSetup
but I couldn't find any reliable tutorial.
Currently there is no REST API endpoint to directly convert some JSON record into a Frame object. Thus, the only way forward for you would be to first write the data to a CSV file, then upload it to h2o using POST /3/PostFile, and then parse using POST /3/Parse.
(Note that POST /3/PostFile endpoint is not in the documentation. This is because it is handled separately from the other endpoints. Basically, it's an endpoint that takes an arbitrary file in the body of the post request, and saves it as "raw data file").
The same job is much easier to do in Python or in R: for example in order to upload some dataset into h2o for scoring, you only need to say
df = h2o.H2OFrame(plaindata)
I am already doing something similar in my project. Since, there is no REST API endpoint to directly convert JSON record into a Frame object. So, I am doing the following: -
1- For Model Building:- first transfer and write the data into the CSV file where h2o server or cluster is running.Then import data into the h2o using POST /3/ImportFiles, and then parse and build a model etc. I am using the h2o-bindings APIs (RESTful APIs) for it. Since I have a large data (hundreds MBs to few GBs), so I use /3/ImportFiles instead POST /3/PostFile as latter is slow to upload large data.
2- For Model Scoring or Prediction:- I am using the Model MOJO and POJO. In your case, you use POST /3/PostFile as suggested by #Pasha, if your data is not large. But, as per h2o documentation, it's advisable to use the MOJO or POJO for model scoring or prediction in a production environment and not to call h2o server/cluster directly. MOJO and POJO are thread safe, so you can scale it using multithreading for concurrent requests.
I want to use Tarantool database for logging user activity.
Are there any out of the box solutions to create web dashboard with nice charts based on the collected data?
A long time ago, using an old-old version of tarantool I've created a draft of tarbon - time-series database, with carbon-cache identical interface.
Since that time the protocol have changed, but the generic idea still the same: use spaces to store data, compact data organization and correct indexes to access spaces as time-series rows and lua for preparing resulting jsons.
That solution was perfect in performance (either on reads or on writes), but that old version lacks disk storage and without disk I was very limited to metrics capacity.
Tarantool has embedded lua language so u could generate json from your data and use any charting library. For example D3.js has method to load json directly from url.
d3.json(url[, callback])
Creates a request for the JSON file at the specified url with the mime type "application/json". If a callback is specified, the request is immediately issued with the GET method, and the callback will be invoked asynchronously when the file is loaded or the request fails; the callback is invoked with two arguments: the error, if any, and the parsed JSON. The parsed JSON is undefined if an error occurs. If no callback is specified, the returned request can be issued using xhr.get or similar, and handled using xhr.on.
You also could look at c3.js simple facade for d3
When I creating same type objects and save them into database, should I send a list of that objects in one request or should I send individually for each one?
For example, I would like to create a todo list, I can create multiple todos, then click save to send a list of todos, or when I finish editing one todo, I save it directly.
The first way can save request numbers, only one request needed to create many objects. But is the first way RESTful? All infomation about create in REST is creating a single object, but will there be poblems if increasing requests numbers?
----Edit
Thank you guys answering me.
For a more spicific usecase, I am using Django Rest Framework. I created a Todo model and a corresponding serializer. I am wondering, how could I create a list of Todos? I tried to send a list of Todos to serializer, and expecting serializer can automatically loop through it as same as getting a list of instance. But that doesn't work. I know I may be able to create a loop to call create method everytime. But is there a better way to do it?
There is nothing in REST that tells you what kind of payload you are allowed to use. You can POST/PUT whatever you want - one entity representation or many representations, in lists, dictionaries, XML, URL-encoded key/values or JSON, what ever suits your use case best.
In your case you might even want to send a delta/diff list of changes on the client: Lets for instance say your client loads some existing 3 todo items. Then the user modifies one of them, deletes another one and adds a new one. You can either do that in three requests or one single request with add/modify/delete operations encoded in it. Both ways are valid and the best solution depends on your use case and constraints like bandwidth, processing power and network round-trip time.
Can a custom REST service be used as a data source for a dojo data grid? I am needing to combine data from three different databases into one data grid. The column data will need to be sort-able. The response from the REST service looks to be correct. I have having trouble with binding the JSON data to the dojo grid columns.
Very interesting -- I tested and saw the same thing with a custom REST service -- it doesn't work when referenced as the storeComponentId of the grid.
I got it to work with the following steps:
Include two dojo modules in the page resources to set up the data store
A pass-thru script tag with code to set up a JSON data store for the grid (uses the dojo modules that the resources specify)
The grid’s store property is set to the variable set up for the data source in the tag. (storeComponentId needs an XPages component name)
Here are some snippets that show the changes:
<xp:this.resources>
<xp:dojoModule name="dojo.store.JsonRest"></xp:dojoModule>
<xp:dojoModule name="dojo.data.ObjectStore"></xp:dojoModule>
</xp:this.resources>
...
<xe:restService id="restService1" pathInfo="gridData">
...
<script>
var jsonStore = new dojo.store.JsonRest(
{target:"CURRENT_PAGE_NAME_HERE.xsp/gridData"}
);
var dataStore = dojo.data.ObjectStore({objectStore: jsonStore});
</script>
...
<xe:djxDataGrid id="djxDataGrid1" store="dataStore">
There's more information and a full sample here:
http://xcellerant.net/dojo-data-grid-33-reading-custom-rest-service/
The easiest way is to start with the extension library. There's a sample for a custom JSON-Rest service. While it pulls data from one source, it is easy to extend to pull data from more than one. I strongly suggest you watch out for all over performance.
What I would do:
create a bean that spits out the JSON to the grid
test it with one database
learn about threads in XPages and here
use one thread each for the databases, cuts down your load time
use a ConcurrentSkipListMap with a comparator so you have the initial JSON in the sort order most useful to the user (or the one from the preferences or the last run)
Memento bene: the Java Collections Framework is your friend (a sometimes difficult one).
Let us know how it goes!