用flask处理图片非常容易,这一篇学习一下图片的上传、下载及展示。还是以实例代码演示为主。
首先,实现一个简单的上传(过程中未做任何处理,只是为了演示)
点击选择图片,输入李四:
html代码:
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<!doctype html> <html lang = "en" > <head> <meta charset = "utf-8" > <title>title< / title> < / head> <body> <div> <form method = "post" action = "http://localhost:5000/up_photo" enctype = "multipart/form-data" > < input type = "file" size = "30" name = "photo" / > <br> < input type = "text" class = "txt_input" name = "name" style = "margin-top:15px;" / > < input type = "submit" value = "提交信息" class = "button-new" style = "margin-top:15px;" / > < / form> < / div> < / body> < / html> |
点击提交信息后,通过 http://localhost:5000/up_photo,传递到后台对应的路由处理,查看控制台:
后台接收的路由代码:
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basedir = os.path.abspath(os.path.dirname(__file__)) @app .route( '/up_photo' , methods = [ 'post' ]) def up_photo(): img = request.files.get( 'txt_photo' ) username = request.form.get( "name" ) path = basedir + "/static/photo/" file_path = path + img.filename img.save(file_path) print '上传头像成功,上传的用户是:' + username return render_template( 'index.html' ) |
此时,我们查看static/photo时,已经可以看到我们点击上传的图片了。
以上是最简单的一个文件上传示例,我们实际使用中基本不可能这样去写,通常会做一些处理。例如:上传后做图片名称唯一性的处理、限制上传文件的类型、无论上传成功或者失败,都去做一些返回提示等等。
限制上传文件类型,例如,我们希望用户上传的文件为图片类型
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allowed_extensions = set ([ 'png' , 'jpg' , 'jpg' , 'png' , 'gif' , 'gif' ]) def allowed_file(filename): return '.' in filename and filename.rsplit( '.' , 1 )[ 1 ] in allowed_extensions |
上面的代码片段通过截取上传文件的后缀名,判断是否是属于我们期望用户上传的类型。
更改上传图片名称,防止重名
这里我们使用日期加随机数生成图片名,做一个生成字符串的工具类
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#-*-coding:utf-8-*- import datetime import random class pic_str: def create_uuid( self ): #生成唯一的图片的名称字符串,防止图片显示时的重名问题 nowtime = datetime.datetime.now().strftime( "%y%m%d%h%m%s" ); # 生成当前时间 randomnum = random.randint( 0 , 100 ); # 生成的随机整数n,其中0<=n<=100 if randomnum < = 10 : randomnum = str ( 0 ) + str (randomnum); uniquenum = str (nowtime) + str (randomnum); return uniquenum; |
当我们点击图片上传,选择图片点击提交后,页面返回提示信息如下图:
此时看我们工程下的upload文件夹,唯一名称的图片已经上传成功
图片的下载
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@app .route( '/download/<string:filename>' , methods = [ 'get' ]) def download(filename): if request.method = = "get" : if os.path.isfile(os.path.join( 'upload' , filename)): return send_from_directory( 'upload' , filename, as_attachment = true) pass |
图片的展示
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# show photo @app .route( '/show/<string:filename>' , methods = [ 'get' ]) def show_photo(filename): file_dir = os.path.join(basedir, app.config[ 'upload_folder' ]) if request.method = = 'get' : if filename is none: pass else : image_data = open (os.path.join(file_dir, '%s' % filename), "rb" ).read() response = make_response(image_data) response.headers[ 'content-type' ] = 'image/png' return response else : pass |
完整示例代码
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#encoding:utf-8 #!/usr/bin/env python from werkzeug.utils import secure_filename from flask import flask, render_template, jsonify, request, make_response, send_from_directory, abort import time import os from strutil import pic_str import base64 app = flask(__name__) upload_folder = 'upload' app.config[ 'upload_folder' ] = upload_folder basedir = os.path.abspath(os.path.dirname(__file__)) allowed_extensions = set ([ 'png' , 'jpg' , 'jpg' , 'png' , 'gif' , 'gif' ]) def allowed_file(filename): return '.' in filename and filename.rsplit( '.' , 1 )[ 1 ] in allowed_extensions @app .route( '/upload' ) def upload_test(): return render_template( 'up.html' ) # 上传文件 @app .route( '/up_photo' , methods = [ 'post' ], strict_slashes = false) def api_upload(): file_dir = os.path.join(basedir, app.config[ 'upload_folder' ]) if not os.path.exists(file_dir): os.makedirs(file_dir) f = request.files[ 'photo' ] if f and allowed_file(f.filename): fname = secure_filename(f.filename) print fname ext = fname.rsplit( '.' , 1 )[ 1 ] new_filename = pic_str().create_uuid() + '.' + ext f.save(os.path.join(file_dir, new_filename)) return jsonify({ "success" : 0 , "msg" : "上传成功" }) else : return jsonify({ "error" : 1001 , "msg" : "上传失败" }) @app .route( '/download/<string:filename>' , methods = [ 'get' ]) def download(filename): if request.method = = "get" : if os.path.isfile(os.path.join( 'upload' , filename)): return send_from_directory( 'upload' , filename, as_attachment = true) pass # show photo @app .route( '/show/<string:filename>' , methods = [ 'get' ]) def show_photo(filename): file_dir = os.path.join(basedir, app.config[ 'upload_folder' ]) if request.method = = 'get' : if filename is none: pass else : image_data = open (os.path.join(file_dir, '%s' % filename), "rb" ).read() response = make_response(image_data) response.headers[ 'content-type' ] = 'image/png' return response else : pass if __name__ = = '__main__' : app.run(debug = true) |
基本示例就以上这些了!
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/weixin_36380516/article/details/80347192