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+ Takes in a URL (string), validates that it's a valid URL. Provides a consistent hashing function which will return the same string. The format of the URL will be of the form `https://shortn/`
+ Users can access URLs and they will be redirected to a long URL.
+ Abuse vectors.
+ Authentication
+ Analytics
1 table, 840 bytes per row.
1 cache mapping with 10k entries. Each entry takes 828 bytes.
Assuming we will need to store 10 million websites, our table will be of size 8.4 GB. This fits in a single server but for resiliency, we will need to use more than one.
Our cache needs 8.2 MB, for resiliency, we will also need multiple servers.
2 endpoints:
+ /api/shortened_url [POST]
+ /
Our database needs a single table called UrlMappings:
UrlMappings:
MappingId: Int (4bytes)
OriginalUrl: string(200 characters) (800 bytes)
ShortenedUrl: string(7 characters) (28 bytes)
CreatedTime: datetime (4 bytes)
Total: 840bytes
2 major user journeys:
+ Users send a request to generate a URL.
The server will query the cache to see if it exists. If it doesn't exist it will query the server to see if the URL exists. If it doesn't exist:
The server will generate a random 6 letter code(capitals included). The server queries the DB until it finds the first code that isn't repeated. The server then inserts it into the DB and the cache.
+ Users send a request to query a certain shortened URL.
Estimate the scale of the system you are going to design...
Define what APIs are expected from the system...
Defining the system data model early on will clarify how data will flow among different components of the system. Also you could draw an ER diagram using the diagramming tool to enhance your design...
You should identify enough components that are needed to solve the actual problem from end to end. Also remember to draw a block diagram using the diagramming tool to augment your design. If you are unfamiliar with the tool, you can simply describe your design to the chat bot and ask it to generate a starter diagram for you to modify...
Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...
Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...
Explain any trade offs you have made and why you made certain tech choices...
Try to discuss as many failure scenarios/bottlenecks as possible.
What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?