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import csv
import io
import boto3
from typing import List, Dict
from .utils import Utilities
class DataReader:
"""
A class to read CSV data from a local file, S3 object, or string. Near
the project completion, support for JSON/Parquet files will be added.
"""
def __init__(self):
self.utils = Utilities()
def read_local(self, path) -> List[Dict[str, str]]:
"""
A method to read a local CSV file and return the data as a list of
dictionaries.
"""
with open(path, mode="r", encoding="utf-8") as f:
return self.read_string(f.read())
def read_s3(self, path) -> List[Dict[str, str]]:
"""
A method to read an S3 object containing CSV data
and return the data as a list of dictionaries.
"""
bucket, key = self.utils.get_s3_path(path)
client = boto3.client("s3")
response = client.get_object(Bucket=bucket, Key=key)
content = response["Body"].read().decode("utf-8")
read_csv_content = self.read_string(content)
return read_csv_content
def read_string(self, content: str) -> List[Dict[str, str]]:
"""
A method to read CSV data from a string and return the data as a list
of dictionaries.
"""
if not content.strip():
return []
f = io.StringIO(content)
reader = csv.DictReader(f)
return [dict(row) for row in reader]
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