Froala Documentation

Flask Image Upload

Image Upload

The following sections describe how to handle image uploads on your server using Flask as a server-side language. For information on the upload workflow refer to the image upload documentation.

Frontend

Setting up the index page.

On the head section include the Editor style.

<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8">
 <link href="https://cdn.jsdelivr.net/npm/froala-editor@latest/css/froala_editor.pkgd.min.css" rel="stylesheet" type="text/css" />
 </head>

On the body section include the Editor JS files and define the area for the editor.

<body> 
 <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/froala-editor@latest/js/froala_editor.pkgd.min.js"></script>
 
 <div class="sample">
 <h2>image upload example.</h2>
 <form>
 <textarea id="edit" name="content"></textarea>
 </form>
 </div>

Initialize the editor and set the image upload URL

 <script>
 new FroalaEditor('#edit', {
 // Set the image upload URL.
 imageUploadURL: '/UploadFiles',
 imageUploadParams: {
 id: 'my_editor'
 }
 })
 </script>
</body>
</html>

The full code should look like this:

<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8">
 <link href="https://cdn.jsdelivr.net/npm/froala-editor@latest/css/froala_editor.pkgd.min.css" rel="stylesheet" type="text/css" />
 </head>
 
 <body>
 <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/froala-editor@latest/js/froala_editor.pkgd.min.js"></script>
 
 <div class="sample">
 <h2>image upload example.</h2>
 <form>
 <textarea id="edit" name="content"></textarea>
 </form>
 </div>
 
 <script>
 new FroalaEditor('#edit', {
 imageUploadURL: '/UploadFiles',
 imageUploadParams: {
 id: 'my_editor'
 }
 })
 </script>
 </body>
</html>

The full code should look like this:

<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8">
 <link href="https://cdn.jsdelivr.net/npm/froala-editor@latest/css/froala_editor.pkgd.min.css" rel="stylesheet" type="text/css" />
 </head>
 
 <body>
 <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/froala-editor@latest/js/froala_editor.pkgd.min.js"></script>
 
 <div class="sample">
 <h2>Image upload example.</h2>
 <form>
 <textarea id="edit" name="content"></textarea>
 </form>
 </div>
 
 <script>
 new FroalaEditor('#edit', {
 imageUploadURL: '/UploadFiles',
 imageUploadParams: {
 id: 'my_editor'
 }
 })
 </script>
 </body>
</html>

Backend

server.py handles the server part for flask

Inside server.py, the Image class handles the image upload

from flask import Flask, request, send_from_directory, jsonify
import base64
import datetime
from os.path import isfile, join
from mimetypes import MimeTypes
from os import listdir
from wand.image import Image
import wand.image
import hashlib
import json
import time
import hmac
import copy
import sys
import os
 
import wand.image
 
# Create public directory at startup.
BASE_DIR = os.path.dirname(os.path.abspath(__file__))
publicDirectory = os.path.join(BASE_DIR, "public")
if not os.path.exists(publicDirectory):
 os.makedirs(publicDirectory)
 
app = Flask(__name__, static_url_path = "")
 
@app.route("/")
def get_main_html():
 return send_from_directory("./", "index.html")
 
@app.route("/public/<path:path>")
def get_public(path):
 return send_from_directory("public/", path)
 
@app.route("/static/<path:path>")
def get_static(path):
 return send_from_directory("./", path)
 
@app.route("/upload_image", methods = ["POST"])
def upload_image():
 try:
 response = Image.upload(FlaskAdapter(request), "/public/")
 except Exception:
 response = {"error": str(sys.exc_info()[1])}
 return json.dumps(response)
 
@app.route("/upload_image_validation", methods = ["POST"])
def upload_image_validation():
 def validation(filePath, mimetype):
 with wand.image.Image(filename = filePath) as img:
 if img.width != img.height:
 return False
 return True
 
 options = {
 "fieldname": "myImage",
 "validation": validation
 }
 
 try:
 response = Image.upload(FlaskAdapter(request), "/public/", options)
 except Exception:
 response = {"error": str(sys.exc_info()[1])}
 return json.dumps(response)
 
 
class Image(object):
 
 defaultUploadOptions = {
 "fieldname": "file",
 "validation": {
 "allowedExts": ["gif", "jpeg", "jpg", "png", "svg", "blob"],
 "allowedMimeTypes": ["image/gif", "image/jpeg", "image/pjpeg", "image/x-png", "image/png",
 "image/svg+xml"]
 },
 # string resize param from http://docs.wand-py.org/en/0.4.3/guide/resizecrop.html#transform-images
 # Examples: "100x100", "100x100!". Find more on http://www.imagemagick.org/script/command-line-processing.php#geometry
 "resize": None
 }
 
 @staticmethod
 def upload(req, fileRoute, options = None):
 """
 Image upload to disk.
 Parameters:
 req: framework adapter to http request. See BaseAdapter.
 fileRoute: string
 options: dict optional, see defaultUploadOptions attribute
 Return:
 dict: {link: "linkPath"}
 """
 if options is None:
 options = Image.defaultUploadOptions
 else:
 options = Utils.merge_dicts(Image.defaultUploadOptions, options)
 
 return File.upload(req, fileRoute, options)
 
 @staticmethod
 def delete(src):
 """
 Delete image from disk.
 Parameters:
 src: string
 """
 return File.delete(src)
 
 @staticmethod
 def list(folderPath, thumbPath = None):
 """
 List images from disk.
 Parameters:
 folderPath: string
 thumbPath: string
 Return:
 list: list of images dicts. example: [{url: "url", thumb: "thumb", name: "name"}, ...]
 """
 if thumbPath == None:
 thumbPath = folderPath
 
 # Array of image objects to return.
 response = []
 absoluteFolderPath = Utils.getServerPath() + folderPath
 
 # Image types.
 imageTypes = Image.defaultUploadOptions["validation"]["allowedMimeTypes"]
 
 # Filenames in the uploads folder.
 fnames = [f for f in listdir(absoluteFolderPath) if isfile(join(absoluteFolderPath, f))]
 
 for fname in fnames:
 mime = MimeTypes()
 mimeType = mime.guess_type(absoluteFolderPath + fname)[0]
 if mimeType in imageTypes:
 response.append({
 "url": folderPath + fname,
 "thumb": thumbPath + fname,
 "name": fname
 })
 
 return response
 
 
class Utils(object):
 """
 Utils static class.
 """
 
 @staticmethod
 def hmac(key, string, hex = False):
 """
 Calculate hmac.
 Parameters:
 key: string
 string: string
 hex: boolean optional, return in hex, else return in binary
 Return:
 string: hmax in hex or binary
 """
 # python 2-3 compatible:
 try:
 hmac256 = hmac.new(key.encode() if isinstance(key, str) else key, msg = string.encode("utf-8") if isinstance(string, str) else string, digestmod = hashlib.sha256) # v3
 except Exception:
 hmac256 = hmac.new(key, msg = string, digestmod = hashlib.sha256) # v2
 
 return hmac256.hexdigest() if hex else hmac256.digest()
 
 @staticmethod
 def merge_dicts(a, b, path = None):
 """
 Deep merge two dicts without modifying them. Source: http://stackoverflow.com/questions/7204805/dictionaries-of-dictionaries-merge/7205107#7205107
 Parameters:
 a: dict
 b: dict
 path: list
 Return:
 dict: Deep merged dict.
 """
 aClone = copy.deepcopy(a);
 # Returns deep b into a without affecting the sources.
 if path is None: path = []
 for key in b:
 if key in a:
 if isinstance(a[key], dict) and isinstance(b[key], dict):
 aClone[key] = Utils.merge_dicts(a[key], b[key], path + [str(key)])
 else:
 aClone[key] = b[key]
 else:
 aClone[key] = b[key]
 return aClone
 
 @staticmethod
 def getExtension(filename):
 """
 Get filename extension.
 Parameters:
 filename: string
 Return:
 string: The extension without the dot.
 """
 return os.path.splitext(filename)[1][1:]
 
 @staticmethod
 def getServerPath():
 """
 Get the path where the server has started.
 Return:
 string: serverPath
 """
 return os.path.abspath(os.path.dirname(sys.argv[0]))
 
 @staticmethod
 def isFileValid(filename, mimetype, allowedExts, allowedMimeTypes):
 """
 Test if a file is valid based on its extension and mime type.
 Parameters:
 filename string
 mimeType string
 allowedExts list
 allowedMimeTypes list
 Return:
 boolean
 """
 # Skip if the allowed extensions or mime types are missing.
 if not allowedExts or not allowedMimeTypes:
 return False
 
 extension = Utils.getExtension(filename)
 return extension.lower() in allowedExts and mimetype in allowedMimeTypes
 
 @staticmethod
 def isValid(validation, filePath, mimetype):
 """
 Generic file validation.
 Parameters:
 validation: dict or function
 filePath: string
 mimetype: string
 """
 # No validation means you dont want to validate, so return affirmative.
 if not validation:
 return True
 
 # Validation is a function provided by the user.
 if callable(validation):
 return validation(filePath, mimetype)
 
 if isinstance(validation, dict):
 return Utils.isFileValid(filePath, mimetype, validation["allowedExts"], validation["allowedMimeTypes"])
 
 # Else: no specific validating behaviour found.
 return False
 
 
class BaseAdapter(object):
 """
 Interface. Inherit this class to use the lib in your framework.
 """
 
 def __init__(self, request):
 """
 Constructor.
 Parameters:
 request: http request object from some framework.
 """
 self.request = request
 
 def riseError(self):
 """
 Use this when you want to make an abstract method.
 """
 raise NotImplementedError( "Should have implemented this method." )
 
 def getFilename(self, fieldname):
 """
 Get upload filename based on the fieldname.
 Parameters:
 fieldname: string
 Return:
 string: filename
 """
 self.riseError()
 
 def getMimetype(self, fieldname):
 """
 Get upload file mime type based on the fieldname.
 Parameters:
 fieldname: string
 Return:
 string: mimetype
 """
 self.riseError()
 
 def saveFile(self, fieldname, fullNamePath):
 """
 Save the upload file based on the fieldname on the fullNamePath location.
 Parameters:
 fieldname: string
 fullNamePath: string
 """
 self.riseError()
 
 
class FlaskAdapter(BaseAdapter):
 """
 Flask Adapter: Check BaseAdapter to see what methods description.
 """
 
 def checkFile(self, fieldname):
 if fieldname not in self.request.files:
 raise Exception("File does not exist.")
 
 def getFilename(self, fieldname):
 self.checkFile(fieldname)
 return self.request.files[fieldname].filename
 
 def getMimetype(self, fieldname):
 self.checkFile(fieldname)
 return self.request.files[fieldname].content_type
 
 def saveFile(self, fieldname, fullNamePath):
 self.checkFile(fieldname)
 file = self.request.files[fieldname]
 file.save(fullNamePath)

Additional Resources

Video Upload

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URL: https://froala.com/wysiwyg-editor/docs/server/flask/image-upload/

⇱ Image Upload Flask Integration Guide