I'm no back-end developer. So perspective is always appreciated.
I have written a script which requests from an API and creates this huge JSON file I want to save in firebase, how can I accomplish this? And would it be possible to filter this json with python for example; when I add region=eu in the url this returns the objects which have Europe as region or do I absolutely need to request the entire json file and parse in my code (java android) ?
Since there are a few parts to your question:
You can save JSON to Firebase and the data will be mapped to child locations:
Using PUT, we can write a string, number, boolean, array or any JSON object to our Firebase database...When a JSON object is saved to the database, the object properties are automatically mapped to child locations in a nested fashion.
https://firebase.google.com/docs/database/rest/save-data
And for your next question:
And would it be possible to filter this json with python for example; when I add region=eu in the url this returns the objects which have Europe as region
Looks like you should be able to jimmy something together with Firebase's filters, startAt and endAt:
We can combine startAt and endAt to limit both ends of our query.
https://firebase.google.com/docs/database/rest/retrieve-data#section-rest-filtering
For your example you might do something like this:
curl 'https://yourfirebase.firebaseio.com/yourendpoint.json?orderBy="$REGION_NAME"&startAt="EU"&endAt="EU"&print=pretty'
...or do I absolutely need to request the entire json file and parse in my code (java android) ?
The facts that JSON objects are stored hierarchically in Firebase and that you can filter based on those object values makes me think you do not, in fact, have to request the entire JSON file. However, I don't have personal experience with this particular aspect of Firebase, so give it a shot!
As #ackushiw mentions in the comments, you can also use the equalTo query (https://firebase.google.com/docs/reference/js/firebase.database.Query#equalTo):
curl 'https://yourfirebase.firebaseio.com/yourendpoint.json?orderBy="$REGION_NAME"&equalTo="EU"&print=pretty'
It really depends on how you are structuring your JSON. It's generally recommended to make your JSON tree as shallow as possible since all children are loaded when you have a matching query.
FIREBASE DATA:
{
"-id1": {
"region": "eu" // bear in mind queries are case sensitive
"title": "Foo"
"nested": {
"city": "berlin"
}
},
"-id2": {
"region": "other"
"title": "Bar"
"nested": {
"city": "berlin"
}
},
"-id3": {
"region": "eu"
"title": "Baz"
"nested": {
"city": "paris"
}
}
}
Querying with (using the Android API)
.orderByChild("region").equalTo("eu")
would return "-id1" and "-id3"
with
.orderByChild("nested/city").equalTo("berlin")
would return "-id1" and "-id2"
The REST API Returns Unsorted Results: JSON interpreters do not enforce any ordering on the result set. While orderBy can be used in combination with startAt, endAt, limitToFirst, or limitToLast to return a subset of the data, the returned results will not be sorted. Therefore, it may be necessary to manually sort the results if ordering is important.
If you're using a more complex structure I recommend watching this video
https://www.youtube.com/watch?v=vKqXSZLLnHA
I'd also recommend using the firebase library for Android
https://firebase.google.com/docs/android/setup
And Firebase-UI, It does a lot for you.
https://firebaseopensource.com/projects/firebase/firebaseui-android/
I have a json file on server:
{"images":[
{"url":"...", "likes":"123"},
{"url":"...", "likes":"234"},
{"url":"...", "likes":"345"}
]}
I get the json file on android read it, but if someone likes a picture i want to change the value of the first picture from 123 to 124, is this possible and how can i do this?
The whole point is to change a json value on server,from client side.
Also if this isn't possible how can i make this happen?
Also if i want to get the Top50 rated pictures,how can i sort them and get only the 50 picture,without getting all pictures and sorting them on android ?
Which one is better,initializing the Top50 images,when the user starts the app,or when the user click on the button Top50.I assume that if its when he click the button,there might be some performance issues server side?
My other idea is to have a function server side,which every 10 min,executes automatically and gets the Top50 rated and makes something like json file.So it all happens server side automatically.
To make this happen, client should expose some interface, i.e. function that will allow to modify file on server side. The interface and implementation of this function greatly depends on server itself, i.e. which protocols it handles, what built-in or external modules it supports, which languages are supported, etc... For example, the classic scenario is using apache as HTTP server, CGI enabled, and write CGI function in perl. So, in this case interface would look like http://server.name/like.cgi?image=image123.
How to modify the values on the server ?
For this every like of a photo should be a post request of this sort.
{
"data": [
{
"image_id": 3133456,
"likes": 343
},
{
"image_id": 3133456,
"likes": 343
}
]
}
On parsing this request server updates the corresponding image's like on the server.
How to get the top 50 rated/liked images from the server ?
Again you send a get request to such a url
http://server.getsomething.com/getTop50Images
On server side
On receiving such a request you make a query on the table in your database something like this
select image_id , image_url, likes from image_table limit 50 ORDER BY likes ASC
Now getting those query results and returning them as a json would not be a performance hit until you have huge bulk of data. like some million rows may be in your database.
Response can be something like this
{
"result": [
{
"image_id": 3133456,
"likes": 34400,
"url": "http://flickr.com/someimage"
},
{
"image_id": 3133456,
"likes": 34380,
"url": "http://flickr.com/someimage"
}
]
}
You still avoid using a database yourself but can lease it from clouds services like parse.
However if you won't be using those services then you can take a look at ftp packages for js. Like the neo JavaScript library by apache.
But still a good choice will be to go with the database approach (is quiet simpler).
I have to submit data from 30 pages into the server.These datas from 30 pages are to be made into a single string and that i have to upload that single string into the server using json.
Each page may contain many answers tht may be either in plain text(value we receive from edit text),from check boxes(yes or no) and so on.....please suggest me a way to add all these data into a single string and upload it using json.
Based on the comment I suspect that you believe that you need to treat these "pages" as strings that you concat. However, what I think you're overlooking is that JSON is pretty versatile in how you add objects to it.
So, let's say you have the thing that you want to ship to your server and you call it
JSONObject myEntireFile = new JSONObject();
you can now add stuff to it at any time like this...
JSONObject page1 = new JSONObject();
myEntireFile.put("page1", page1);
meanwhile you can put whatever you want IN page 1 (cause that's just another serialized container).
You can keep doing this until you're ready to send it, at which time you just call
myEntireFile.toString();
which will convert your object into one long, well formatted, JSON string, that you can then open store for later use.
Suppose I have a json string like this:
{ ... "key1":"value1"; ... }
with a key1-value1 pair somewhere deep down the json structure (which includes other things such as array, dictionary, etc...). I don't know exactly (and don't care) how the exact structure of the json is.
Is there a simple way to extract the "value1" ? (if there are 2 "key1" in the json string then I just need the first one).
As far as I know, you have no chance of doing it manually.
If you really don't know what's the structure of the JSON string you're expecting, you can try a graph search approach, such as DFS (http://en.wikipedia.org/wiki/Depth-first_search).
For every key, check if it is an array.
If so, go inside and repeat the procedure. If nothing was found in a given array, backtrack.
Interrupt your process once you have found your key.
Hi, I am new to android. I want to get data from webservice. in which key's are store in an array . and ley values stores in another array. In webservice data are display like,
{"1":{"para_id":"1","para_parent_id":"0","para_level":"0","para_type":"0","para_value":"Salution","para_desc":"Salution","para_sort_order":"1","para_tech_desc":"Salution","created_dt":"2011-08-11 19:47:05","created_by":"1","updated_dt":"2011-08-11 19:47:05","updated_by":"1","status":"A"},"1001":{"para_id":"1001","para_parent_id":"1","para_level":"0","para_type":"1","para_value":"Mr.","para_desc":"Mr.","para_sort_order":"1","para_tech_desc":"Mr.","created_dt":"2011-08-11 19:47:21","created_by":"1","updated_dt":"2011-08-11 19:47:21","updated_by":"1","status":"A"},"1002":{"para_id":"1002","para_parent_id":"1","para_level":"0","para_type":"1","para_value":"Ms.","para_desc":"Ms.","para_sort_order":"1","para_tech_desc":"Ms.","created_dt":"2011-08-11 19:49:00","created_by":"1","updated_dt":"2011-08-11 19:49:00","updated_by":"1","status":"A"},"1003":{"para_id":"1003","para_parent_id":"1","para_level":"0","para_type":"1","para_value":"Mrs.","para_desc":"Mrs.","para_sort_order":"1","para_tech_desc":"Mrs.","created_dt":"2011-08-12 09:40:14","created_by":"1","updated_dt":"2011-08-12 09:40:14","updated_by":"1","status":"A"},"2":{"para_id":"2","para_parent_id":"0","para_level":"0","para_type":"0","para_value":"Appointment Types","para_desc":"Appointment Types","para_sort_order":"1","para_tech_desc":"Appointment Types","created_dt":"2011-08-16 15:43:15","created_by":"1","updated_dt":"2011-08-16 15:43:15","updated_by":"1","status":"A"},"2001":{"para_id":"2001","para_parent_id":"2","para_level":"0","para_type":"2","para_value":"Scheduled","para_desc":"Scheduled","para_sort_order":"1","para_tech_desc":"Scheduled","created_dt":"2011-08-16 15:43:36","created_by":"1","updated_dt":"2011-08-16 15:43:36","updated_by":"1","status":"A"},"2002":{"para_id":"2002","para_parent_id":"2","para_level":"0","para_type":"2","para_value":"Cancelled","para_desc":"Cancelled","para_sort_order":"1","para_tech_desc":"Cancelled","created_dt":"2011-08-16 15:43:51","created_by":"1","updated_dt":"2011-08-16 15:43:51","updated_by":"1","status":"A"},"2003":{"para_id":"2003","para_parent_id":"2","para_level":"0","para_type":"2","para_value":"Re-Scheduled","para_desc":"Re-Scheduled","para_sort_order":"1","para_tech_desc":"Re-Scheduled","created_dt":"2011-08-16 15:44:24","created_by":"1","updated_dt":"2011-08-16 15:44:24","updated_by":"1","status":"A"},"2004":{"para_id":"2004","para_parent_id":"2","para_level":"0","para_type":"2","para_value":"Deleted","para_desc":"Deleted","para_sort_order":"1","para_tech_desc":"Deleted","created_dt":"2011-08-16 15:44:38","created_by":"1","updated_dt":"2011-08-16 15:44:38","updated_by":"1","status":"A"},"3":{"para_id":"3","para_parent_id":"0","para_level":"0","para_type":"0","para_value":"Customer Status","para_desc":"Customer Status","para_sort_order":"1","para_tech_desc":"Customer Status","created_dt":"2011-08-29 12:51:48","created_by":"1","updated_dt":"2011-08-29 12:51:48","updated_by":"1","status":"A"},"3001":
I want to sore key "1" ,"2", "3" in an array and related value in another array.and get the data. How can i do this?
Well, this looks like JSON, so use a JSON-Parser, for a tutorial see here. You can make your JSON more readable (especially when asking on SO) using the JSON beautifier