File size: 4,908 Bytes
17e2002 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 | <h4><strong>Our Flask API Template Code </strong></h4><p><br></p><p>In the previous chapter, we created a Web App that's accessible via the web browser. Pretty cool! but what if we wanted to call this API from different Apps e.g. a Native Android or iOS App?</p><p><br>Let's turn it into RESTful API that returns simple JSON responses encapsulating the results. </p><p><strong>NOTE</strong>: A <strong>RESTful API</strong> is an application program interface (<strong>API</strong>) that uses HTTP requests to GET, PUT, POST and DELETE data.</p><p><br></p><p><strong>Step 1: </strong>Firstly, install <strong>Postman </strong>to test our API </p><ul><li><p>Windows/Max - <a href="https://www.getpostman.com/downloads/" rel="noopener noreferrer" target="_blank">Download and install here </a></p></li><li><p>Ubuntu Users - Launch Ubuntu Software and Install </p></li></ul><figure><img src="https://udemy-images.s3.amazonaws.com:443/redactor/raw/2019-04-23_06-16-17-a75ad1a8a678b5837139fcab17cd4f6f.JPG"></figure><p><strong>Step 2: </strong>Our Flask API Code</p><pre class="prettyprint linenums">import os
from flask import Flask, flash, request, redirect, url_for, jsonify
from werkzeug.utils import secure_filename
import cv2
import numpy as np
import keras
from keras.models import load_model
from keras import backend as K
UPLOAD_FOLDER = './uploads/'
ALLOWED_EXTENSIONS = set(['png', 'jpg', 'jpeg'])
DEBUG = True
app = Flask(__name__)
app.config.from_object(__name__)
app.config['SECRET_KEY'] = '7d441f27d441f27567d441f2b6176a'
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
def allowed_file(filename):
return '.' in filename and \
filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS
@app.route('/', methods=['GET', 'POST'])
def upload_file():
if request.method == 'POST':
# check if the post request has the file part
if 'file' not in request.files:
flash('No file part')
return redirect(request.url)
file = request.files['file']
# if user does not select file, browser also
# submit an empty part without filename
if file.filename == '':
flash('No selected file')
return redirect(request.url)
if file and allowed_file(file.filename):
filename = secure_filename(file.filename)
file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
image = cv2.imread(os.path.dirname(os.path.realpath(__file__))+"/uploads/"+filename)
color_result = getDominantColor(image)
dogOrCat = catOrDog(image)
#return redirect(url_for('upload_file',filename=filename)), jsonify({"key":
return jsonify({"MainColor": color_result, "catOrDog": dogOrCat} )
return '''
<!doctype html>
<title>API</title>
<h1>API Running Successfully</h1>'''
def catOrDog(image):
'''Determines if the image contains a cat or dog'''
classifier = load_model('./models/cats_vs_dogs_V1.h5')
image = cv2.resize(image, (150,150), interpolation = cv2.INTER_AREA)
image = image.reshape(1,150,150,3)
res = str(classifier.predict_classes(image, 1, verbose = 0)[0][0])
print(res)
print(type(res))
if res == "0":
res = "Cat"
else:
res = "Dog"
K.clear_session()
return res
def getDominantColor(image):
'''returns the dominate color among Blue, Green and Reds in the image '''
B, G, R = cv2.split(image)
B, G, R = np.sum(B), np.sum(G), np.sum(R)
color_sums = [B,G,R]
color_values = {"0": "Blue", "1":"Green", "2": "Red"}
return color_values[str(np.argmax(color_sums))]
if __name__ == "__main__":
app.run()</pre><figure><img src="https://udemy-images.s3.amazonaws.com:443/redactor/raw/2019-04-23_00-48-49-5db46541ad63d65d835cdd569211c973.JPG"></figure><p><strong>Using Postman (see image above and the corresponding numbered steps below:</strong></p><ol><li><p>Change the protocol to POST</p></li><li><p>Enter the local host address: http://127.0.0.1:5000/</p></li><li><p>Change Tab to Body</p></li><li><p>Select the form-data radio button</p></li><li><p>From the drop-down, select Key type to be file</p></li><li><p>For Value, select one of our test images</p></li><li><p>Click send to send our image to our API</p></li><li><p>Our response will be shown in the window below.</p></li></ol><p>The output is JSON file containing:</p><pre class="prettyprint linenums">{
"MainColor": "Red",
"catOrDog": "Cat"
}</pre><p>The cool thing about using Postman is that we can generate the code to call this API in several different languages:</p><p>See blue box to bring up the code box:</p><figure><img src="https://udemy-images.s3.amazonaws.com:443/redactor/raw/2019-04-23_00-54-19-04fa84ce24394a4b9df2347dee6ac632.jpg"></figure><p>Code Generator</p><figure><img src="https://udemy-images.s3.amazonaws.com:443/redactor/raw/2019-04-23_00-55-22-1aaeea8249c6c70d464a1ece0466b273.JPG"></figure><p><strong>Now that you've got your Flask API and Web App working, let's look at deploying this on AWS using an EC2 Instance.</strong></p> |