Developed Rest Api using Spring Boot framework based on Controller -> Service -> Repository model.
Implemented on HATEOAS architecture pattern.
Using H2 in memory DB for persistence. Configured JPA ORM layer to talk to H2.
Use Etag headers for synchronization of updates. Other option was to use Last update time or VERSION ATTRIBUTE for syncronization , but wanted to ake sure hashing of object`s content would me more accurate to achieve syncronization.
1.Steps
1. Make sure maven is availble on your machine
2: From a terminal/console create a directory (eg:Test)
3: cd Test
4: git init
4: git clone https://github.com/sudha-bhargavi/myprojects.git
5: This will create application repo under the current Test directory called myprojects
6: cd myprojects
7:In this directory create a directory called seeddata. This directory holds the data pulled from IMDB.
8:Extract and copy the 5 seeddata files(seedata.zip provided as an gmail drive link) into this seeddata directory
9: CastAndCrew.csv Episode.csv Principals.csv Ratings.csv Titles.csv
10: Next place the moviedb.mv.db file in the HOME directory eg : ~/moviedb. This will help pre start the db with
out creating it again from scratch.(Extract from , moviedb.zip provided via shared google drive link)
11: Structure of the current directoty Test/myprojects should now look like this:
pom.xml seeddata src target
12: From the directory myprojects run the command mvn spring-boot:run
Or you can run application from any IDE IntelliJ / Eclipse by importing the project as maven project.
This will run Apache server and deploy application on localhost port 8080
13: I am using in memory H2 Database for persisting the data. This is configured to look into ~/moviedb
for file persistence between restarts of the server.
http://localhost:8080/h2 will bring up the DB console.Username sa No password
jdbc URL for h2 console: jdbc:h2:~/moviedb
14: Open a rest client like postman and access the following URLs to run application.
Make sure every request is in new tab if testing from postman
- Testing
1: All getAll APIs are paginated with 20 items for each page with page metadata included.
This is to achieve HATEOS style architecture.
2:URL GET: localhost:8080/movies
This API will pull all 2017 movies , their ratings if exitis and other details.
3:URL GET: localhost:8080/tvSeries
This API will pull all 2017 tvSeries, ratings and their seson ratings and cast info if exists.
4: URL GET: localhost:8080/tvSeries/{id} localhost:8080/movies/{id}
This API will pull a movie or tvSeries with the give ID, and its ratings and their seson ratings.
5: URL GET: localhost:8080/tvSeries/{id}/rating
This API will return the tvseries rating
6: URL GET : http://localhost:8080/tvSeries/{id}/season/{seasonnum}/episodes
This API will return all the episodes that belong to a season of a tvSeries.
Using this we can see what the ratings of each indiccidual episode is.
Average of all the episodes rating is the season rating
7: URL GET http://localhost:8080/tvSeries/{id}/season/{seasonnum}/rating
This API will return a seasons rating.
Average of all the episodes rating is the season rating
TvSeries with ID tt10016348 "http://localhost:8080/tvSeries/tt10016348" has 2 seasons
GET Call this API to see the list of episodes as below:
http://localhost:8080/tvSeries/tt10016348/season/1/episodes
Season1 has 10 episdoes as below with null rating for each episode
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020066",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 1
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020068",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 2
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020070",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 3
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020072",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 4
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020074",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 5
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020076",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 6
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020080",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 7
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020082",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 8
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020084",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 9
},
{
"rating": {
"rating": null,
"votes": null,
"movieId": null,
"links": []
},
"episodeId": "tt10020090",
"tvSeriesId": "tt10016348",
"seasonNum": 1,
"episodeNum": 11
}
Hence when we do a GET on Season 1`s rating we get 0 rating value
"http://localhost:8080/tvSeries/tt10016348/season/1/rating" (use Etag header If-Match = 47602)
Now do a put on one of the episodes tt10020072 , rating by calling
PUT http://localhost:8080/tvSeries/tt10020090/rating with (Notice here the Id is episode ID)
Eg: payload
{
"rating": 20.0,
"votes": 10,
"movieId": "tt10020090"
}
First time you get a precondition failure status where the server will respond back with an Etag. Copy Etag from the
server response header and invoke the request again with request Header param as If-Match = <Etagvalue> and above
payload. This should update the season rating to new value.
Lets requery the season rating using http://localhost:8080/tvSeries/tt10016348/season/1/rating
first call will return an 204 with non content and a new Etag as the seasons rating got updated with the change in its
episode rating. Resend the Get request with the new Etag and get the new rating which should be avg value of all non
null episodes. In this case just one episode.
For syncronization I am using EntityTags (ETag) headers (If-Match header) in the client requests to solve
LOST updates. This way we can achieve optimistic locking on the resource updates.
URL: PUT localhost:8080/tvSeries/{id}/rating
Sample PUT payload for updating the rating of an episode with id tt10014818
{
"movieId": "tt10014818"
"rating": 210.0,
"votes": 20,
}
The above is a PUT Api call where we can update the rating for a movie or tvseries or an episode.Server is
made to handle concurrency where the request is expected to have an IF-Match Etag header. When a request is
made to update the episode rating we verify if the request has "If-Match" header with a value. This value is
compared against the ETag value on the server side. If it matches that implies the resource has not been
updated and thisupdate can proceed. If the values do not match then server returns a Precondition failure
status with the new Etag. Client can update hi knowlegde of the resource and rerequest with the new updated
Etag.Syncronization: When two concurrrent updates happen, ETag in the header will allow the request to update
a resource only if the Etags on the server side match . Request 1 with Etag1 updates a resource. Request 2
with ETag1 will now fail and will retry with the updated resoucre and new ETag. This is more of an optimistic
approach.
Some integration tests have been added to the application to test the above usecases.
Add ORM Caching level caching
Implement security of rest APIs with Oauth tokens using a OAuth protocol and end to end using TLS.
Planned on providng a SWAGGER API document. Due to time constarint could not finish the Swagger spec details. Partial not much usable
Swagger link is availble here http://localhost:8080/swagger-ui.html#!
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