Sheffield | 25-SDC-Nov | Sheida Shabankari | Sprint 3 |Middleware exercises #64
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Two comments to understand. Don't bother fixing the bug unless you fancy the stretch objective. Otherwise solid code.
| //Middleware #۱: | ||
| app.use((req,res,next)=>{ | ||
| const usernameHeader=req.headers["x-username"]; | ||
| req.username=usernameHeader ? usernameHeader : null; |
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This works, but would more often be seen as
req.username = usernameHeader ?? null;
or
req.username = usernameHeader || null;
An interesting exercise is to understand the difference between these two and why the first is better.
| app.use((req,res,next)=>{ | ||
| let data=''; | ||
| req.on('data',chunk => { | ||
| data+=chunk; |
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There is a subtle bug here. chunk is bytes, not a string. data+=chunk will do a convert to string. In UTF8 a single character can be as many as 4 bytes (even though most are 1). If the chunk happens to end in the middle of a long character, the conversion to string will go wrong. You're saving concatenating all the bytes first and then converting to string afterwards. It's probably out of scope for this exercise though.
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Description:
This PR adds two directories for the middleware exercises:
middleware-custom/ – Express app with two custom middlewares: reading X-Username header and parsing/validating JSON array POST body.
middleware-express-json/ – Same app using Express’s built-in express.json() middleware instead of custom body parsing.
Both apps have a POST endpoint returning authentication status and requested subjects.