Definition
For OGHR, Platform needs to enable user to undertake exams. Platform should be capable of processing the user responses and evaluate these responses with relevant applicable scores. Outcome of this design should enable the platform users to take up examination with server side evaluation of results.
Background
In the present system, Question Set consist of following entities:
Entities
Assessment User : Active seeker of Assessment in the platform.
QuML Player : QuML Player has capability to play the questions in QuML format. It also has capability to locally validate the user input. Response Validation,Score Computing is completely handled in player. Once User Submits the overall response, client validated scores and response are updated using Content State Update API.
Flink Jobs : Flink Jobs aggregates the content state using Collection Activity Aggregator, Collection Assessment Aggregator, Cert Pre-processor, Cert Generator jobs.
Objective Types:
a) MCQ (Multiple Choice Questions)
b) MSQ (Multiple Select Questions)
c) MTF (Match The Following)
d) FTB (Fill in The Blanks)
Subjective Types
a) VSA - (Very Short Answer)
b) SA - (Short Answer)
c) LA - (Long Answer)
Building Blocks :
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Building Blocks
...
API
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Flink Jobs
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Sunbird InQuiry
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Question Set Hierarchy API
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Question List Read API
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QuestionSet Create API
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Question Create API
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Sunbird Lern
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Content State Read
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Collection Activity Aggregate
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Content State Update
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Collection Assessment Aggregate
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Enrollment List API
...
Cert Pre Processer
...
Cert Generator
...
Sunbird RC
...
Cert Registry Download API
Current Workflow
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Design PreRequisites :
Allow the response processing of question to be done on server rather than client as happening today.
Scalable Response Processing Solution for Question Sets.
Score Calculation Based on Content State Update.
Solution to the question needs to be masqueraded or excluded from the Question Read API/ Question List API.
Response Processing can happen in two ways:
Entire Question Set Response Processing
Question by Question Response Processing
Solution Proposed
Proposed System:
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Technical Design Details:
QuestionSet Hierarchy API : A new attribute in QuestionSet to be introduced to have evaluated response on server. (“evaluable“). Every QuestionSet Hierarchy will attach “QuestionSetToken“ based on encrypted value of user-id, questionset-id, collection-id.
| Code Block |
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"questionSet": {
"timeLimits": "{\"maxTime\":\"3600\"}",
"questionSetToken": "", //#Question Set Digest to be generated at hierarchy read API with combination of "Question Set ID + userID"
"evaluable": true //#true for Server Side Valuation Default:#false for client side validation
} |
Question Read API : Any Question Associated with evaluable behaviour to trim off response declaration from Question Set. Instead a responseKey to be shared along with responseDeclaration. responseKey is encrypted value of response. This is permenantly persisted as encrypted. Only QuestionRead API with questionCreator access should be able to access the decrypted value on demand.
| Code Block |
|---|
"evaluable": true,
"responseDeclaration": {
"response1": {
"maxScore": 1,
"cardinality": "single",
"type": "integer",
-- To be Trimmed off ----
"correctResponse": {
"value": "0",
"outcomes": {
"SCORE": 1
}
},
-- To be Trimmed off --
#Newly Introduced Attribute
"responseKey": "#Computed Hash/Encrypted Value of the result"
}
}, |
Question Create API:
It is possible to permanently mark the question to be “evaluable“ in nature. Any evaluable question would automatically qualify for evaluable question Set. These Questions can be part of Evaluable QuestionSet only. Question Read of Evaluable Questions should exhibit the behaviour mentioned above.
Question Creation API should accept the response from the Question Creator to generate the encrypted value of the response created. This responseKey will be persisted along with Question metadata. Since the actual response is encrypted there is no effective mechanism to derive the right answer. Any Subsequent question Read API will only generate responses with encryptString without actual result.
| Info |
|---|
KeySet (Futuristic): Any Responses on Question Set can be persisted separately to ensure the keyset can be used for administrative purposes. |
QuestionResponseValidateAPI (Async API Behaviour):
API accepts the request payload similar to content state update API. Along with responseKeys in the assessment.
| Code Block |
|---|
{
"request": {
"userId": "843a9940-720f-43ed-a415-26bbfd3da9ef",
"questionSetDigest": "",
"assessments":[
{
"assessmentTs": 1681284869464,
"batchId": "0132677340746629120",
"collectionId": "do_213267731619962880127",
"userId": "843a9940-720f-43ed-a415-26bbfd3da9ef",
"attemptId": "5486724f41afb4997118e6d97695684f",
"contentId": "do_2129959063404544001107"
},
responses:[{
"identifier":"<question-id>",
"questionType": "",
"userResponse":[""],
"responseDeclaration": {},
"responseKey":["<response-key>"]
}]
}],
"contents": [
{
"contentId": "do_2132671468826214401203",
"batchId": "0132677340746629120",
"status": 2,
"courseId": "do_213267731619962880127",
"lastAccessTime": "2023-04-12 12:56:45:687+0530"
},
]
}
} |
The Above payload mimics ContentStateUpdate API to mimic responses as above.
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| title | Reference Call for Content State Update |
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Definition
For OGHR, Platform needs to enable user to undertake exams. Question set evaluation is currently on the client side and this implies that the correct answer is available to the client. We need to introduce the capability to process the user responses, evaluate and compute scores on the server side so that the correct answer does not have to be sent to the client side.
...
Background
In the present system, Question Set consist of following :
Assessment User : Active seeker of Assessment in the platform.
QuML Player : QuML Player has capability to play the questions in QuML format. It also has capability to evaluate and compute score. Response Validation, Score Computing is completely handled in player as of now. Once User Submits the overall response, client validated scores and response are sent to the backend as ASSESS events using Content State Update API.
Question Editor : Question Set Editor enables the sourcing of question and questionSet in the system.
Flink Jobs : Flink Jobs aggregates the content state using Collection Activity Aggregator, Collection Assessment Aggregator, Cert Pre-processor, Cert Generator jobs.
Question Types
Objective Types:
a) MCQ (Multiple Choice Questions)
b) MSQ (Multiple Select Questions)
c) MTF (Match The Following)
d) FTB (Fill in The Blanks)
Subjective Types
a) VSA - (Very Short Answer)
b) SA - (Short Answer)
c) LA - (Long Answer)
Building Blocks :
Building Blocks | API | Flink Jobs |
|---|---|---|
Sunbird InQuiry | Question Set Hierarchy API | |
Question List Read API | ||
QuestionSet Create API | ||
Question Create API | ||
Sunbird Lern | Content State Read | Collection Activity Aggregate |
Content State Update | Collection Assessment Aggregate | |
Enrollment List API | Cert Pre Processer | |
Cert Generator | ||
Sunbird RC | Cert Registry Download API |
...
Solution of Problem :
Allow the assessment evaluation to be done on server for question sets that are chosen to be server evaluable.
Answers to the question needs to be excluded from the Question Read API/ Question List API for server side assessment evaluation questions.
...
Current Workflow
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Solution Proposed
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Technical Design Details:
Creation side Enhancements:
Introduce “eval“ : {“mode“ : “client/server“} attribute at question and questionSet Object Metadata level
A new attribute in QuestionSet to be introduced to mark it for server side evaluation. The editor need to allow setting this flag on a questionSet/questions. The creation APIs would be updated to support this attribute. Any question that is marked as “eval” : { “mode“ : “server“ } can only be part of a questionSet that is also marked as “eval” : { “mode“ : “server“ } . Also a question set that is marked “eval” : { “mode“ : “server“ } should only contain questions with “eval” : { “mode“ : “server“ }.
(“evaluate at server “).
| Code Block | ||
|---|---|---|
| ||
//Question Set Object
"questionSet": {
“eval” : { “mode“ : “server“ } //#true for Server Side Valuation Default:#false for client side validation
}
//Question Object
"question" : {
“eval” : { “mode“ : “server“ }
} |
Consumption side Enhancements
There are two modes of accessing questionSet post this proposed change:
a) evaluable-mode : default ( In case eval attribute does not exist or mode = client)
In this mode, theplayer uses the new GET questionSetHierarchy to fetch the hierarchy, existing question list API to fetch question body and the existing content state update API to submit the ASSESS events. Calculation of assess score remains at client side.
b) evaluable-mode : server
| Info |
|---|
Content Compatibility needs to be set to higher value so that discovery on older clients dont happen for this questionSet |
We are proposing that, in this mode, the player uses the new POST questionSetHierarchy to fetch the hierarchy, the existing question list API and the existing Content State Update API without passing “score” & “pass”. Content State Update will fetch “score“ & “pass“ using new Inquiry Assessment API which introduced as part of this feature.
QuestionSet Hierarchy API (new POST API)
The current questionsetHierarchy API is a get call and does not take in arguments. Introduce a new POST method for QuestionSet Hierarchy API that can take in request body. This API will have payload as follows
| Code Block | ||
|---|---|---|
| ||
{
"request": {
"questionset": {
"contentID": "",
"collectionID": "",
"userID": "",
"attemptID": ""
}
}
} |
This API would handle shuffling of options , selection of a subset of questions and randomisation (currently done by player) as indicated by the metadata in the questionSet. The API will also return a “QuestionSetToken“ which is a signed token contains user-id, content-id, collection-id,attempt-id+selected_questionid_list received , eval mode as part of hierarchy payload. This token will further be passed to Content State Update & to new submitAssessment API from Content State Update.“QuestionSetToken“ will be validated by submitAssessment API call.
| Code Block | ||
|---|---|---|
| ||
"questionSet": {
"timeLimits": "{\"maxTime\":\"3600\"}",
"questionSetToken": "", //#Question Set token to be generated at hierarchy read API with combination of "Question Set ID + userID"
“eval” : { “mode“ : “server“ } //#true for Server Side Valuation Default:#false for client side validation
} |
| Info |
|---|
QuestionSetToken : This key is almost equivalent of jwt token created as follows: { "contentID":"do_11381896937577676811", "evalMode":"server", "collectionID":"do_11381130283086643213", "userID":"user-id", "questionList":"<do-id-1>,<do-id-2>,….<do-id-n>", "attemptID":"attempt-id" } } |
2. Updates to QuestionList API
Question Read API : Any Question Associated with eval-mode-server behaviour to trim off response declaration from Question Set and other answer displayed reference parameters in the response.
| Code Block |
|---|
"serverEvaluable": true,
"responseDeclaration": {
"response1": {
"maxScore": 1,
"cardinality": "single",
"type": "integer",
-- To be Trimmed off ----
"correctResponse": {
"value": "0",
"outcomes": {
"SCORE": 1
}
},
-- To be Trimmed off --
}
}, |
There are multiple attributes which persists correct answer in QuML
a) responseDeclaration: (Shown above)
b) answer
c) editorState
3. Assessment API to evaluate user responses & calculate score.
QuestionResponseValidateAPI (Sync API Behaviour):
QuestionSetToken generated in Hierarchy is sent as part of this request. This token will help validate that the responses are submitted for the questions that were given out to this user and also verify the time of submission.
API accepts the request payload similar to content state update API.
| Code Block | ||
|---|---|---|
| Code Block | ||
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{ "request": { "userId": "843a9940-720f-43ed-a415-26bbfd3da9ef", "type questionSetToken": "User "}, "context":{"channel":"0126796199493140480","pdata":{"id":"staging.sunbird.portal","ver":"5.2.0","pid":"sunbird-portal.contentplayer"},"env":"contentplayer","sid":"hiv7abkP2ptQEspxLosgzBh_WeQAMcyt","did":"dfab80b18d8ce5d4df8159ba05dde951","cdata":[{"id":"do_213267732169023488128","type":"course"},{"type":"batch","id":"0132677340746629120"},{"id":"af588b6a747b6b3d28bea6d947dfbc49","type":"ContentSession"},{"id":"1a20fb335ff8dada7802d4473fe1a55e","type":"PlaySession"}],"rollup":{"l1":"0126796199493140480"}},"object":{"id":"do_2129959063404544001107","type":"Content","ver":"2","rollup":{"l1":"do_213267732169023488128","l2":"do_2129959063404544001107"}},"tags":["0126796199493140480"],"edata":{"item":{"id":"do_21299582901864857613016","maxscore":1,"type":"ftb","exlength":0,"params":[{"1":"{\"text\":\"\"}"},{"2":"{\"text\":\"\"}"},{"3":"{\"text\":\"\"}"},{"eval":"order"}],"uri":"","title":"Registration","mmc":[],"mc":[],"desc":""},"index":1,"pass":"No","score":0,"resvalues":[{"1":"{\"text\":\"Sharath\"}"},{"2":"{\"text\":\"10\"}"},{"3":"{\"text\":\"CSE\"}"}],"duration":16}},{"eid":"ASSESS","ets":1681284892463,"ver":"3.1","mid":"ASSESS:e57069e81c8e561915b20de23969e7ab","actor":{"id":"843a9940-720f-43ed-a415-26bbfd3da9ef","type":"User"},"context":{"channel":"0126796199493140480","pdata":{"id":"staging.sunbird.portal","ver":"5.2.0","pid":"sunbird-portal.contentplayer"},"env":"contentplayer","sid":"hiv7abkP2ptQEspxLosgzBh_WeQAMcyt","did":"dfab80b18d8ce5d4df8159ba05dde951","cdata":[{"id":"do_213267732169023488128","type":"course"},{"type":"batch","id":"0132677340746629120"},{"id":"af588b6a747b6b3d28bea6d947dfbc49","type":"ContentSession"},{"id":"1a20fb335ff8dada7802d4473fe1a55e","type":"PlaySession"}],"rollup":{"l1":"0126796199493140480"}},"object":{"id":"do_2129959063404544001107","type":"Content","ver":"2","rollup":{"l1":"do_213267732169023488128","l2":"do_2129959063404544001107"}},"tags":["0126796199493140480"],"edata":{"item":{"id":"do_21299582796158566413015","maxscore":1,"type":"ftb","exlength":0,"params":[{"1":"{\"text\":\"\"}"},{"eval":"order"}],"uri":"","title":"Edit test UT","mmc":[],"mc":[],"desc":""},"index":2,"pass":"No","score":0,"resvalues":[{"1":"{\"text\":\"1\"}"}],"duration":4}}]}]}}' \ --compressed |
Question Set Response Processing flow
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Question Set Response Processing Hardening
In Order to minimise the possiblity of Exam Response replays or any other kind of malpractices. Following design enhancement is proposed.
Usage of QuestionSetDigest:
A Hash value of “user-id+questionsetid+timestamp“ is generated as questionSetDigest and sent to client as part of Question Hierarchy.
Same Digest is used in QuestionValidation API request payload to validate the userID and questionSetID tampering.
QuestionList Validation
In order to check for validity of Question inside a QuestionSet. Design proposes the value to be encrypted based on QuestionID List in hierarchy and persist this information against QuestionSetDigest in Redis.
| Code Block | ||||
|---|---|---|---|---|
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console.time("dbsave");
var crypto = require('crypto');
var encryptList = [];
var string = "sdgxsoksgdaodjqwdhuwdh";
var count = 0;
var salt = "salty";
for(var i=0;i<1000000;i++) {
var encrypt = crypto.pbkdf2('secret'+i, salt, 10, 64, 'sha512', (err, derivedKey) => {
if (err) throw err;
});
encryptList.push(encrypt);
if(string === encrypt) {
count++;
}
}
console.log(count);
console.log(encryptList.length);
console.timeEnd("dbsave"); |
Response Times for Benchmarking
1000000 encrypt generation dbsave: 4011.281ms 100000 encrypt generation dbsave: 377.208ms 10000 encrypt generation dbsave: 57.326msassessments":[ { "assessmentTs": 1681284869464, "batchId": "0132677340746629120", "collectionId": "do_213267731619962880127", "userId": "843a9940-720f-43ed-a415-26bbfd3da9ef", "attemptId": "5486724f41afb4997118e6d97695684f", "contentId": "do_2129959063404544001107" }, "events":[], }], "contents": [ { "contentId": "do_2132671468826214401203", "batchId": "0132677340746629120", "status": 2, "courseId": "do_213267731619962880127", "lastAccessTime": "2023-04-12 12:56:45:687+0530" }, ] } } |
The Above payload mimics ContentStateUpdate API to mimic responses as above.
| Expand | ||
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Question Set Response Processing flow
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Future Reference :
Questions List Validation using back-end persistence
Current design validity check of assigned Questions from QuestionSet collection proposes assigned list of questionIds to be added in the JWT during hierarchy call & validate same during New Inquiry Assessment API. Storing same in Redis & Cassandra is an option which currently not considered.
Scalable server side response processing for Question Sets.
Response Processing can happen in two ways:
Entire Question Set Response Processing (Current solution scope)
Question by Question Response Processing