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Kevin Xu
2019-05-30 13:06:32 +08:00
parent 8149cc0f3d
commit ca677e0701
1 changed files with 8 additions and 8 deletions
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solutions/system_design/pastebin/README.md
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@@ -70,7 +70,7 @@ Without an interviewer to address clarifying questions, we'll define some use ca
Handy conversion guide: Handy conversion guide:
* 2.5 million requests per month * 2.5 million seconds per month
* 1 request per second = 2.5 million requests per month * 1 request per second = 2.5 million requests per month
* 40 requests per second = 100 million requests per month * 40 requests per second = 100 million requests per month
* 400 requests per second = 1 billion requests per month * 400 requests per second = 1 billion requests per month
@@ -108,7 +108,7 @@ An alternative to a relational database acting as a large hash table, we could u
The `pastes` table could have the following structure: The `pastes` table could have the following structure:
```sql ```
shortlink char(7) NOT NULL shortlink char(7) NOT NULL
expiration_length_in_minutes int NOT NULL expiration_length_in_minutes int NOT NULL
created_at datetime NOT NULL created_at datetime NOT NULL
@@ -130,7 +130,7 @@ To generate the unique url, we could:
* Base 64 is another popular encoding but provides issues for urls because of the additional `+` and `/` characters * Base 64 is another popular encoding but provides issues for urls because of the additional `+` and `/` characters
* The following [Base 62 pseudocode](http://stackoverflow.com/questions/742013/how-to-code-a-url-shortener) runs in O(k) time where k is the number of digits = 7: * The following [Base 62 pseudocode](http://stackoverflow.com/questions/742013/how-to-code-a-url-shortener) runs in O(k) time where k is the number of digits = 7:
```python ```
def base_encode(num, base=62): def base_encode(num, base=62):
digits = [] digits = []
while num > 0 while num > 0
@@ -142,7 +142,7 @@ def base_encode(num, base=62):
* Take the first 7 characters of the output, which results in 62^7 possible values and should be sufficient to handle our constraint of 360 million shortlinks in 3 years: * Take the first 7 characters of the output, which results in 62^7 possible values and should be sufficient to handle our constraint of 360 million shortlinks in 3 years:
```python ```
url = base_encode(md5(ip_address+timestamp))[:URL_LENGTH] url = base_encode(md5(ip_address+timestamp))[:URL_LENGTH]
``` ```
@@ -155,7 +155,7 @@ $ curl -X POST --data '{ "expiration_length_in_minutes": "60", \
Response: Response:
```json ```
{ {
"shortlink": "foobar" "shortlink": "foobar"
} }
@@ -174,13 +174,13 @@ For internal communications, we could use [Remote Procedure Calls](https://githu
REST API: REST API:
```shell ```
$ curl https://pastebin.com/api/v1/paste?shortlink=foobar $ curl https://pastebin.com/api/v1/paste?shortlink=foobar
``` ```
Response: Response:
```json ```
{ {
"paste_contents": "Hello World", "paste_contents": "Hello World",
"created_at": "YYYY-MM-DD HH:MM:SS", "created_at": "YYYY-MM-DD HH:MM:SS",
@@ -194,7 +194,7 @@ Since realtime analytics are not a requirement, we could simply **MapReduce** th
**Clarify with your interviewer how much code you are expected to write**. **Clarify with your interviewer how much code you are expected to write**.
```python ```
class HitCounts(MRJob): class HitCounts(MRJob):
def extract_url(self, line): def extract_url(self, line):