COMP3322代写、Java/Python程序语言代做

日期：2023-12-01 11:18

COMP3322 Modern Technologies on World Wide Web

Assignment Four

Total 12 points

Deadline: 23:59 December 3, 2023

Overview

Write an express.js program and name it index.js. This program provides the API to get data about

big cities from a MongoDB server.

Objectives

1. A learning activity to support ILO 1 and ILO 2.

2. To practice how to use Node, Express, MongoDB, and Mongoose to create a simple REST API.

Specification

Assume you are using the MongoDB server running on the course’s node.js docker container with

the service name mongodb listening to the default port 27017.

The database is named "bigcities" and it contains a collection called "cities". The collection consists

of 34800 cities with a population of at least 10000. The data for this dataset is sourced from the

GeoNames geographical database (https://www.geonames.org/about.html). Each record in the

collection consists of 9 fields: _id, Name, “ASCII Name”, “ISO Alpha-2”, “ISO Name EN”, Population,

Timezone, “Modification date”, and Coordinates.

_id Name ASCII Name ISO Alpha-2 ISO Name EN

The id of record

in Geonames

database

The name of the

city (in UTF8)

The name of

the city (in

ASCII)

The ISO 3166

Alpha-2 country

code

The English

name of the

Alpha-2 code

Example 1 3862981 Cañada de Gómez Canada de

Gomez

AR Argentina

Example 2 1819729 Hong Kong Hong Kong HK Hong Kong,

China

Population Timezone Modification

date

Coordinates

The population

of the city

The IANA timezone

ID

The date of

last

modification

The latitude and

longitude values

of the city

Example 1 36000 America/Argentina/

Cordoba

2020-06-10 -32.81636,

-61.39493

Example 2 7482500 Asia/Hong Kong 2021-09-09 22.27832,

114.17469

Download the big cities dataset (bigcities.csv) from the course’s Moodle site. Import the data to the

bigcities database for the tests.

You will be using the provided framework for developing your program. You can download the

template file (template.txt) from the course’s Moodle site.

index.js

const express = require('express')

const app = express();

/* Implement the logic here */

// error handler

app.use(function(err, req, res, next) {

res.status(err.status || 500);

res.json({'error': err.message});

});

app.listen(3000, () => {

console.log('Weather app listening on port 8000!')

});

TASK A

Use the command mongoimport to import the CSV file to the MongoDB server. Here are the steps to

import the data to your docker’s mongodb server.

1. Use Windows Explorer or Mac Finder to go to the data/db folder (which is inside the Nodedev folder).

2. Copy the bigcities.csv file there.

3. Access the docker desktop and open a terminal for the c33322-mongo container.

4. In the terminal, type this command (in one line):

mongoimport -d=bigcities -c=cities --type=csv --headerline --columnsHaveTypes --file=bigcities.csv

Write the code to set up a connection to the MongoDB server using Mongoose.

Use the following schema to access the database.

Schema {

Name: String,

'ASCII Name': String,

'ISO Alpha-2': String,

'ISO Name EN': String,

Population: Number,

Timezone: String,

'Modification date': String,

Coordinates: String

}

Write the code that monitors the database connection and terminates the program if the connection

to the database is lost.

TASK B

Write a routing endpoint to handle all GET requests to the URL

http://localhost:3000/cities/v1/all?gte=xxxxx&lte=yyyyy

for retrieving the entire big cities dataset or a portion of the dataset based on the population range

defined in the query string. The server should respond with a JSON message and an appropriate

HTTP status code that reflects the completion status of the GET request to the client.

Situations:

1. GET /cities/v1/all

When the GET request is made without a query string,

the program retrieves the entire dataset from the

database. It then converts the Coordinates field to an

object with two properties: ‘lat’ and ‘lng’. These

properties represent the latitude and longitude values

(both of type Number) of the city. The program returns

the entire dataset in JSON format to the client with the

HTTP status code 200. The returned JSON message is an

array that contains all the documents, ordered by the _id

field.

2. GET /cities/v1/all?gte=xxxxx

GET /cites/v1/all?lte=yyyyy

GET /cities/v1/all?gte=xxxxx&lte=yyyyy

When the GET request includes a query string with the ‘gte’ and/or ‘lte’ parameters, the

program retrieves the dataset from the database based on the population range specified by the

query string. ‘gte’ stands for  and ‘lte’ stands for . For example, the program retrieves all cities

with a population  one million for the parameter gte=1000000. Another example, the program

retrieves all cities with a population between 500000  x  1000000 for the parameters

gte=500000&lte=1000000. After retrieving the dataset, the program should convert the

Coordinates field to an object and sort the dataset in descending order of population. The

program then returns the dataset in JSON format to the client with HTTP status code 200.

The program should return a JSON string '{"error":"No record for this population

range"}' with the HTTP status code 404 when it could not find any documents matching the

limit defined by the parameters, e.g., lte=1000&gte=10000.

3. When the program experiences an error (e.g., database issue), it returns the HTTP status code

500 with a JSON string '{"error":$message}', where $message stands for the error message

of that error event.

TASK C

Create a routing endpoint that handles all GET requests to the URLs

http://localhost:3000/cities/v1/alpha

http://localhost:3000/cities/v1/alpha/{code}

for retrieving all the alpha codes in the dataset or all the documents in the dataset that match a

specified alpha code in the URL path. The server should respond with a JSON message and the

appropriate HTTP status code to indicate the completion status of the GET request.

Situations:

1. /cities/v1/alpha

With this GET request, the program searches the database to find

all unique alpha-2 codes in the dataset. For each alpha-2 code, the

program creates an object with two properties: 'code' and 'name',

which contain the values from the ISO Alpha-2 and ISO Name EN

fields, respectively. The program then groups all alpha-2 code

objects into an array and sorts them in ascending order based on

the alpha-2 codes. Finally, the program returns this array object as

a JSON message to the client with a status code of 200.

2. /cities/v1/alpha/{code}

With this GET request, the program searches the database to

retrieve all documents that match the specified alpha code in the

path. For example, if the requested path is '/cities/v1/alpha/HK', the

program will find all documents with the 'HK' alpha-2 code. For each

matched document, the program retrieves the following fields:

“ASCII Name”, Population, Timezone, and Coordinates. It converts

the Coordinates field to an object and groups all matched

documents in descending order based on population. The program

then returns this array object as a JSON message to the client with

status code 200.

The program should return a JSON string ‘{“error”:”No record for this alpha code”}’

with the HTTP status code 404 when it could not find any documents matching the requested

alpha code.

3. When the program experiences an error (e.g., database issue), it returns the HTTP status code

500 with a JSON string ‘{“error”:$message}’, where $message stands for the error message

of that error event.

TASK D

Create a routing endpoint that handles all GET requests to the URLs

http://localhost:3000/cities/v1/region

http://localhost:3000/cities/v1/region/{region}

for retrieving all the regions in the dataset or all the documents in the dataset that match a specified

region in the URL path. In response, the server returns a JSON message and appropriate HTTP status

code to the client, which reflects the completion status of the GET request.

Situations:

1. /cities/v1/region

With this request, the program retrieves the Timezone field of all

documents and extracts the first component of the Timezone field to be

the region. For example, if the Timezone value is

"America/Argentina/Cordoba", the program will extract the region as

"America". The program then returns all unique regions in the dataset as a

JSON message to the client with the HTTP status code 200. The JSON

message lists all regions in alphabetical order.

2. /cities/v1/region/{region}

With this GET request, the program searches the database

to retrieve all documents that have the first component of

the Timezone field matches the specified region in the

URL path. For example, if the requested path is

'/cities/v1/region/Atlantic', the program will find 72

documents. For each matched document, the program

retrieves only the following fields: “ASCII Name”, “ISO

Alpha-2”, “ISO Name EN”, Population, Timezone, and

Coordinates. It converts the Coordinates field to an object

and groups all matched documents in descending order

based on population. The program then returns this array

object as a JSON message to the client with status code

200.

The program should return a JSON string ‘{“error”:”No record for this region”}’ with

the HTTP status code 404 when it could not find any documents matching the requested region.

3. When the program experiences an error (e.g., database issue), it returns the HTTP status code

500 with a JSON string ‘{“error”:$message}’, where $message stands for the error message

of that error event.

TASK E

Create a routing endpoint that handles all GET requests to the URL

http://localhost:3000/cities/v1/{city}?partial=true&alpha=xx&region=yyyy&sort=alpha|pop

ulation

for retrieving all the documents in the dataset that match the specified city in the URL path. In

response, the server returns a JSON message and appropriate HTTP status code to the client, which

reflects the completion status of the GET request.

Situations:

1. /cities/v1/{city}

With this GET request, the program retrieves all documents in the database that have the “ASCII

Name” field exactly matches with the specified city name in the URL path. For example, when

the city name is “Logan”, the program returns only one document; whereas for the city name

“Paris”, it returns 4 matched documents. For each matched document, the program retrieves

the following fields only: _id, “ASCII Name”, “ISO Alpha-2”, “ISO Name EN”, Population,

Timezone, and Coordinates. It converts the Coordinates field to an object and groups all

matched documents in ascending order based on the _id field. The program then returns this

array object as a JSON message to the client with status code 200.

2. /cities/v1/{city}?partial=true

When a query string is provided with the parameter

“partial=true”, the program finds all documents where the

“ASCII Name” field partially matches with the specified city

name in the URL path. For example, when the city name is

“Logan”, the program returns 6 matched documents that

have the string “Logan” in their “ASCII Name” fields. If the

parameter “partial” has a value other than “true”, the

program should ignore this parameter and apply the exactly

match as the searching criteria.

3. /cities/v1/{city}?alpha=xx

/cities/v1/{city}?region=yyyy

When the query string contains the “alpha” parameter, the

program restricts the search to documents under this alpha

code for the exactly or partially matched of the city name

(based on the partial parameter). For example, if a search is performed on the city name "Logan"

with partial=true and alpha=AU, only one matched city is found.

When the query string contains the “region” parameter, the program restricts the search to

documents under this region for the exactly or partially matched of the city name. For example,

when searching for the city name “Logan” with partial=true and region=America, five matched

cities are located.

If both the alpha and region parameters are provided, the program should ignore the region

parameter as the alpha parameter should have a higher priority.

4. /cities/v1/{city}?sort=alpha|population

If the sort parameter is not included, the default order will be based on the ascending order of

the _id field. If the sort parameter is included with the value “alpha”, all returned results will be

sorted in ascending order of the alpha code. If the sort parameter is included with the value

“population”, all returned results will be sorted in the descending order of population.

Otherwise, ignore other values and use the default order.

5. The program should return a JSON string ‘{“error”:”No record for this city name”}’

with the HTTP status code 404 when it could not find any documents matching the requested

city name with the parameters.

6. When the program experiences an error (e.g., database issue), it returns the HTTP status code

500 with a JSON string ‘{“error”:$message}’, where $message stands for the error message

of that error event.

TASK F

Write a routing endpoint to intercept all other request types and paths, which are not defined in

previous tasks. Return a JSON string with the HTTP status code 400. For example, for the request

POST /cities/v1/all HTTP/1.1, we get the response '{"error":"Cannot POST

/cities/v1/all"}'; for the request GET /cities/alpha/AU HTTP/1.1, we get the response

'{"error":"Cannot GET /cities/alpha/AU"}'.

Resources

You are provided with the following files.

• template.txt – the framework for the index.js file.

• bigcities.csv – the big cities data set.

Testing platform

We shall run the server program in the node-dev container set and use Curl and Firefox to test the

API.

Submission

Please finish this assignment before 23:59 December 3, 2023 Sunday. Submit the following files:

1. A JSON file – use mongoexport to export the whole collection from the bigcities database.

Similar to the mongoimport command, you have to open a terminal at the data/db folder

and type the following command (in one line):

mongoexport -d=bigcities -c=cities --jsonArray --sort='{_id: 1}' --out=3035111999.json

Replace 3035111999 with your student ID and upload this JSON file.

2. The complete index.js program and other required files.

3. The package.json file of your express program.

Grading Policy

Points Criteria

2.0 Task A

▪ Database set up, import the data set, and export the data set.

▪ The program can connect and access the MongoDB database.

▪ The program can detect that the database connection is broken.

2.5 Task B

▪ Correctly handle the GET request to return all big cities data

▪ Correctly handle the GET request with query string parameters to return the

specific set of data

▪ Error handling

2.0 Task C

▪ Correctly handle the GET request to retrieve all the alpha-2 code in the big cities

dataset.

▪ Correctly handle the GET request to retrieve all cities that have the matched

alpha-2 code.

▪ Error handling

2.0 Task D

▪ Correctly handle the GET request to retrieve all unique regions in the big cities

dataset.

▪ Correctly handle the GET request to retrieve all cities that have the matched

region.

▪ Error handling

2.5 Task E

▪ Correctly handle the GET request to retrieve all cities that have the matched city

name or partially matched city name.

▪ Correctly handle the GET request to retrieve all cities that have the matched city

name or partially matched city name within a specific region/alpha-2 code and

sorting order.

▪ Error handling

1.0 Task F

▪ Error handling of all unknown methods and paths

-4.0 Using any external libraries.

Plagiarism

Plagiarism is a very serious academic offence. Students should understand what constitutes

plagiarism, the consequences of committing an offence of plagiarism, and how to avoid it. Please

note that we may request you to explain to us how your program is functioning as well as we may

also make use of software tools to detect software plagiarism.