London|25-SDC-NOV| FATMA DEGIRMENCI |Sprint 3|Middleware

[fatmaevin]

Learners, PR Template

Self checklist

• I have titled my PR with Region | Cohort | FirstName LastName | Sprint | Assignment Title
• My changes meet the requirements of the task
• I have tested my changes
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Changelist

Exercise 1: Custom middleware

• Implemented usernameMiddleware to parse X-Username header.
• Implemented bodyParser middleware to manually parse POST JSON body as an array of strings.
• Endpoint /subjects responds with authentication info and list of subjects.
• Validates input and rejects invalid JSON or non-string arrays.

Exercise 2: Built-in middleware

• Removed custom bodyParser.
• Added Express built-in express.json() middleware.
• Added bodyMiddleware to ensure POST body is an array of strings.
• Endpoint /subjects behavior remains the same.

[OracPrime]

There is a subtle bug in terms of how you combine the chunks. Feel free to fix it as a stretch objective, but I think it's outside scope for this exercise. Otherwise good code.

[OracPrime]

Because the data is coming in as bytes, there is a risk here. data+=chunk will convert the chunk to string before adding it to data. But some characters in UTF8 can be up to 4 bytes long. If the chunk ends in the middle of such a character, this string conversion will go wrong. Safer is to concatenate the chunks as bytes and then convert to string at the end. Or cheat slightly and use the express text middleware to get the body as a string in one go.