Querying data on json saved using ReJSON - redis

i have saved one json using Rejson against a key,now i would like to filter/query out data using ReJson.
Please let me know how can i do it ...python prefered .
print("Abount to execute coomnad")
response=redisClient.execute_command('JSON.SET', 'object', '.', json.dumps(data))
print(response)
reply = json.loads(redisClient.execute_command('JSON.GET', 'object'))
print(reply)
using the above code i was able to set data using ReJson .now lets suppose i want to filer data .
my test json is :
data = {
'foo': 'bar',
'ans': 42
}
How can you filter say json in which foo has value as bar


Redis in general, and ReJSON specifically, do not provide search-by-value functionality. For that, you'll have to either index the values yourself (see https://redis.io/topics/indexes) or use RediSearch.

Related

Need Pentaho JSON without array

I wanted to output json data not as array object and I did the changes mentioned in the pentaho document, but the output is always array even for the single set of values. I am using PDI 9.1 and I tested using the ktr from the below link
https://wiki.pentaho.com/download/attachments/25043814/json_output.ktr?version=1&modificationDate=1389259055000&api=v2
below statement is from https://wiki.pentaho.com/display/EAI/JSON+output
Another special case is when 'Nr. rows in a block' = 1.
If used with empty json block name output will looks like:
{
"name" : "item",
"value" : 25
}
My output comes like below
{ "": [ {"name":"item","value":25} ] }

I have resolved myself. I have added another JSON input step and defined as below
$.wellDesign[0] to get the array as string object

Pentaho JsonInput GET fields

I'm trying to use PDI to read data from an API (json) and now I'm simply trying to use json input to get a few specific fields but the get fields button on the input step gives me.
ERROR (version 8.3.0.0-371, build 8.3.0.0-371 from 2019-06-11 11.09.08 by buildguy) : Index 1 out of bounds for length 1
all the steps execute fine, and produce data - just not the json input step doesn't wnat to give me the fields option! - I've tired the text file and json oput and both write valid json so IDK whats going on....
PS. this is my first time using PDI
ISSUE 2:
It looks like PDI uses jayway for its json path parsing so I've been using this site https://jsonpath.herokuapp.com/ jayway selection which gives me my expected path. When I put that into the 'fields' of the json input dialog I only get the FIRST instance of that path value vs it actually parsing the json and giving me every instance, and can't figure out why though I assume it has something to do with PDI's row based view on things but I also don't know how to get it to understand that its json and it should be giving me back all values that match that path.
UPDATE 1:
I've been looking at this https://forums.pentaho.com/threads/135882-Parsing-JSON-data-without-knowing-field-names/ it seems like this Modified Java Script Value step might be the way to go. Will continue testing.
UPDATE 2
OK - Used the MJSV as posted above along with a select fields step and finally able to get the key's
var obj = JSON.parse(mydata);
var keys = Object.keys(obj);
for (var i = 0; i < Object.keys(obj).length; i++) {
var row = createRowCopy(getOutputRowMeta().size());
var idx = getInputRowMeta().size();
row[idx++] = keys[i];
putRow(row);
}
trans_Status = SKIP_TRANSFORMATION;

Can't figure out how to insert keys and values of nested JSON data into SQL rows with NiFi

I'm working on a personal project and very new (learning as I go) to JSON, NiFi, SQL, etc., so forgive any confusing language used here or a potentially really obvious solution. I can clarify as needed.
I need to take the JSON output from a website's API call and insert it into a table in my MariaDB local server that I've set up. The issue is that the JSON data is nested, and two of the key pieces of data that I need to insert are used as variable key objects rather than values, so I don't know how to extract it and put it in the database table. Essentially, I think I need to identify different pieces of the JSON expression and insert them as values, but I'm clueless how to do so.
I've played around with the EvaluateJSON, SplitJSON, and FlattenJSON processors in particular, but I can't make it work. All I can ever do is get the result of the whole expression, rather than each piece of it.
{"5381":{"wind_speed":4.0,"tm_st_snp":26.0,"tm_off_snp":74.0,"tm_def_snp":63.0,"temperature":58.0,"st_snp":8.0,"punts":4.0,"punt_yds":178.0,"punt_lng":55.0,"punt_in_20":1.0,"punt_avg":44.5,"humidity":47.0,"gp":1.0,"gms_active":1.0},
"1023":{"wind_speed":4.0,"tm_st_snp":26.0,"tm_off_snp":82.0,"tm_def_snp":56.0,"temperature":74.0,"off_snp":82.0,"humidity":66.0,"gs":1.0,"gp":1.0,"gms_active":1.0},
"5300":{"wind_speed":17.0,"tm_st_snp":27.0,"tm_off_snp":80.0,"tm_def_snp":64.0,"temperature":64.0,"st_snp":21.0,"pts_std":9.0,"pts_ppr":9.0,"pts_half_ppr":9.0,"idp_tkl_solo":4.0,"idp_tkl_loss":1.0,"idp_tkl":4.0,"idp_sack":1.0,"idp_qb_hit":2.0,"humidity":100.0,"gp":1.0,"gms_active":1.0,"def_snp":23.0},
"608":{"wind_speed":6.0,"tm_st_snp":20.0,"tm_off_snp":53.0,"tm_def_snp":79.0,"temperature":88.0,"st_snp":4.0,"pts_std":5.5,"pts_ppr":5.5,"pts_half_ppr":5.5,"idp_tkl_solo":4.0,"idp_tkl_loss":1.0,"idp_tkl_ast":1.0,"idp_tkl":5.0,"humidity":78.0,"gs":1.0,"gp":1.0,"gms_active":1.0,"def_snp":56.0},
"3396":{"wind_speed":6.0,"tm_st_snp":20.0,"tm_off_snp":60.0,"tm_def_snp":70.0,"temperature":63.0,"st_snp":19.0,"off_snp":13.0,"humidity":100.0,"gp":1.0,"gms_active":1.0}}
This is a snapshot of an output with a couple thousand lines. Each of the numeric keys that you see above (5381, 1023, 5300, etc) are player IDs for the following stats. I have a table set up with three columns: Player ID, Stat ID, and Stat Value. For example, I need that first snippet to be inserted into my table as such:
Player ID Stat ID Stat Value
5381 wind_speed 4.0
5381 tm_st_snp 26.0
5381 tm_off_snp 74.0
And so on, for each piece of data. But I don't know how to have NiFi select the right pieces of data to insert in the right columns.

I believe that it's possible to use jolt to transform your json into a format:
[
{"playerId":"5381", "statId":"wind_speed", "statValue": 0.123},
{"playerId":"5381", "statId":"tm_st_snp", "statValue": 0.456},
...
]
then use PutDatabaseRecord with json reader.
Another approach is to use ExecuteGroovyScript processor.
Add new parameter to it with name SQL.mydb and link it to your DBCP controller service
And use the following script as Script Body parameter:
import groovy.json.JsonSlurper
import groovy.json.JsonBuilder
def ff=session.get()
if(!ff)return
//read flow file content and parse it
def body = ff.read().withReader("UTF-8"){reader->
new JsonSlurper().parse(reader)
}
def results = []
//use defined sql connection to create a batch
SQL.mydb.withTransaction{
def cmd = 'insert into mytable(playerId, statId, statValue) values(?,?,?)'
results = SQL.mydb.withBatch(100, cmd){statement->
//run through all keys/subkeys in flow file body
body.each{pid,keys->
keys.each{k,v->
statement.addBatch(pid,k,v)
}
}
}
}
//write results as a new flow file content
ff.write("UTF-8"){writer->
new JsonBuilder(results).writeTo(writer)
}
//transfer to success
REL_SUCCESS << ff

store data into a path based on a field's value in the tuple

{'aaa', 'bbb', 'ccc'}
....
Let's suppose above tupple gets loaded with following schema:
as (firstField:chararray, secondField:chararray, thirdField:chararray)
I want to store the tuple in HDFS with the path based on 2nd field (which is 'bbb' in above example). So the above tuple would get stored in the path
/SomeBaseDir/bbb/testoutput.txt
Any help would be appreciated.

To load the file use below command. Remember the file input data should be tab separated.If you are using any other separator like comma then change the parameter passes in PigStorage funtion. It should be PigStorage(',')
A = load '/home/abhishek/Work/pigInput/data' using PigStorage('\t') as (firstField:chararray, secondField:chararray, thirdField:chararray);
Now, to get the second element simple use:
result = foreach A generate secondField;
Result
dump result
('bbb')
You can store it using below command
store result into 'provide the path';

I think you want to use MultiStorage (https://pig.apache.org/docs/r0.8.1/api/org/apache/pig/piggybank/storage/MultiStorage.html). This should do pretty much what you want. Specify base path, then the field on which subdirectories should be based.

The SPLIT operator in PigLatin would do the job here.
For an input data (in) which is loaded, it could be split into different output variable as following:
loadedData = load ' ' as (.. ,somefield, ) using ... ;
SPLIT loadedData INTO
segmentA IF (somefield=='A'),
segmentB IF (somefield=='B'),
OtherSources OTHERWISE;
store segmentA into 'hdfs://<path for data segmentA >' using ....;
store segmentB into 'hdfs://<path for data segmentB >' using ....;

REGEX_EXTRACT error in PIG

I have a CSV file with 3 columns: tweetid , tweet, and Userid. However within the tweet column there are comma separated values.
i.e. of 1 row of data:
`396124437168537600`,"I really wish I didn't give up everything I did for you, I'm so mad at my self for even letting it get as far as it did.",savava143
I want to extract all 3 fields individually, but REGEX_EXTRACT is giving me an error with this code:
a = LOAD tweets USING PigStorage(',') AS (f1,f2,f3);
b = FILTER a BY REGEX_EXTRACT(f1,'(.*)\\"(.*)',1);
The error is:
error: Filter's condition must evaluate to boolean.

In the use case shared, reading the data using PigStrorage(',') will result in missing savava143 (last field value)
A = LOAD '/Users/muralirao/learning/pig/a.csv' USING PigStorage(',') AS (f1,f2,f3);
DUMP A;
Output : A : Observe that the last field value is missing.
(396124437168537600,"I really wish I didn't give up everything I did for you, I'm so mad at my self for even letting it get as far as it did.")
For the use case shared, to extract all the values from CSV file with field values having ',' we can use either CSVExcelStorage or CSVLoader.
Approach 1 : Using CSVExcelStorage
Ref : http://pig.apache.org/docs/r0.12.0/api/org/apache/pig/piggybank/storage/CSVExcelStorage.html
Input : a.csv
396124437168537600,"I really wish I didn't give up everything I did for you, I'm so mad at my self for even letting it get as far as it did.",savava143
Pig Script :
REGISTER piggybank.jar;
A = LOAD 'a.csv' USING org.apache.pig.piggybank.storage.CSVExcelStorage() AS (f1,f2,f3);
DUMP A;
Output : A
(396124437168537600,I really wish I didn't give up everything I did for you, I'm so mad at my self for even letting it get as far as it did.,savava143)
Approach 2 : Using CSVLoader
Ref : http://pig.apache.org/docs/r0.9.1/api/org/apache/pig/piggybank/storage/CSVLoader.html
Below script makes use of CSVLoader(), DUMP A will result in the same output seen earlier.
A = LOAD 'a.csv' USING org.apache.pig.piggybank.storage.CSVLoader() AS (f1,f2,f3);

The error is that you do not want to FILTER based on a regex but GENERATE new fields based on a regex. To filter, you need to know if the line have to be filtered, hence the boolean requirement.
Therefore, you have to use :
b = FOREACH a GENERATE REGEX_EXTRACT(FIELD, REGEX, HOW_MANY_GROUPS_TO_RETURN);
However, as #Murali Rao said, your values are not just coma separated but CSV (think how you will handle a coma in tweet : it is not a field separator, just some content).