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• ‣ ⁃ ◘ ◦ ⦾ ⦿ ✓ ✔ ☑ ☒ ⦿ ⦾ ✪ ☓ ✖ « » ✗ ❞ ❝
♲ ♳ ♴ ♵ ♶ ♷ ♸ ♹ ♺ ♻ ♼ ♽
© ℗ ⓒ ® ™
℃ ℉ °
♡ ♥ ❤ ∞☺☻♂ ♀ ☯
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£ € $ ¢ ¥ ƒ ₧ ؋ ₳ ฿ ₵ ₡ ₢ ₫ ₯ ₠ ₣ ₲ ₴ ₭ ₺ ℳ ₥ ₦ ₱ ₰ 元 圆 圓 ﷼ ₹ ₨ ₪ ₸ ₮ ₩ ¥ 円
α Α ß Β γ Γ δ Δ ε Ε ζ Ζ η Η θ ϴ ι Ι κ Κ λ Λ μ Μ ν Ν ξ Ξ ο Ο π Π ρ Ρ σ Σ τ Τ ϒ Υ φ ϕ ψ Ψ ω Ω
⋆ ✢ ✥ ✦ ✧ ❂ ❉ ✱ ✲ ✴ ✵ ✶ ✷ ✸ ❇ ✹ ✺ ✻ ✼ ❈ ✮ ✡
♒ ♓ ♈ ♉ ♊ ♋ ♌ ♍ ♎ ♏ ♐ ♑
☼ ☽ ☾ ❅ ❆ ϟ ☀ ☁ ☂ ☃ ☄ ☼
♔ ♚ ♕ ♛ ♗ ♝ ♘ ♞ ♙ ♟ ♖ ♜
⌀⌁⌂⍳⍴ ⍵ ⍶ ⍷ ⍸ ⍹ ⍺ ⌃⌄⌅⌆⌇⌈⌉⌊⌋⌌⌍⌎⌏⌐⌑⌒⌓⌔⌕⌖⌗⌘⌙⌚⌛⌜⌝⌞⌟⌠⌡⌢⌣⌤ ⌥ ⌦⌧⌫⌬⌭⌮⌯⌰⌱⌲⌳⌴⌵⌶⌿⍀⍁ ⍂ ⍃ ⍄ ⍅ ⍆ ⍇ ⍈ ⍉ ⍊ ⍋ ⍌ ⍍ ⍎ ⍏ ⍐ ⍒ ⍓ ⍔ ⍕ ⍖ ⍗ ⍘ ⍙ ⍚ ⍜ ⍝ ⍞ ⍟ ⍠ ⍡ ⍢ ⍣ ⍤ ⍥ ⍦ ⍧ ⍨ ⍩ ⍪ ⍫ ⍬ ⍭ ⍮ ⍯ ⍰ ⌷ ⌸ ⌹ ⌺ ⌻ ⌼ ⍱ ﹘﹝﹞
⓪ ① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨
ⓐ ⓑ ⓒ ⓓ ⓔ ⓕ ⓖ ⓗ ⓘ ⓙ ⓚ ⓛ ⓜ ⓝ ⓞ ⓟ ⓠ ⓡ ⓢ ⓣ ⓤ ⓥ ⓦ ⓧ ⓨ ⓩ
Ⓐ Ⓑ Ⓒ Ⓓ Ⓔ Ⓕ Ⓖ Ⓗ Ⓘ Ⓙ Ⓚ Ⓛ Ⓜ Ⓝ Ⓞ Ⓟ Ⓠ Ⓡ Ⓢ Ⓣ Ⓤ Ⓥ Ⓦ Ⓧ Ⓨ Ⓩ
End of exam.
Section C — Implementation and examples (30 marks) 11. (8 marks) Given a simplified workflow: user submits a file-host URL → service validates URL → service retrieves file metadata from host → service returns a premium direct download link. Write a step-by-step sequence (bullet list) of the server-side actions, including error handling at each major step. Provide an example of expected metadata fields returned. 12. (8 marks) Example: The service uses a worker that downloads files to temporary storage before serving. Describe how you would manage temporary storage to avoid disk exhaustion and ensure cleanup. Include example policies (e.g., TTL, size quotas) and a cleanup algorithm. 13. (6 marks) Provide two example API responses (JSON) for: a) Successful conversion including fields: original_url, direct_url, filename, size_bytes, expiry_timestamp. b) Error response when the host is unsupported. 14. (8 marks) Write pseudo-code (high-level, language-agnostic) for validating a submitted URL to ensure it matches one of the supported hosts and is well-formed. Include at least one example of a regex or pattern used for matching a host.
Duration: 90 minutes Total marks: 100
Section D — Security, privacy, and ethics (20 marks) 15. (6 marks) Identify and explain four security risks specific to a premium link generator service and a brief mitigation for each. 16. (6 marks) Discuss privacy considerations for handling user-submitted URLs and any associated credentials. Recommend three concrete privacy-preserving practices. 17. (8 marks) Ethical question: Some users claim the service "saves money" by avoiding paid subscriptions. Analyze the ethical and legal implications and state a clear position on operating such a service. Provide an example scenario illustrating your point.