blob

Js实现Blob视频加密（附代码，精讲）

由 狂风中的少年 提交于 2019-12-21 19:23:51
Js实现Blob视频加密（附代码，精讲） 一、原理 把video的src属性以blob形式给显示出来，这样就可以实现加密效果。示例效果如下： 二、过程 利用Ajax方法，请求一个视频地址，并设置返回值为Blob类型 把请求的数据传给video的src属性 video接收到src属性后，就立即释放请求到的数据，以免泄露。 三、示例代码 < video id = "my-video" class = "video-js" playsinline controls preload = "auto" controlslist = "nodownload" controlslist = "nofullscreen" width = "100%" height = "240" poster = "./public/images/cover.png" > < / video > < script type = "text/javascript" > var video = document . getElementById ( "my-video" ) ; window . URL = window . URL || window . webkitURL ; //用来判断电脑系统window.webkitURL和window.URL是一样的，window.URL标准定义，window

How to obtain the size of a BLOB without reading the BLOB's content

由 微笑、不失礼 提交于 2019-12-21 17:17:19
问题 I have the following questions regarding BLOBs in sqlite: Does sqlite keep track of sizes of BLOBs? I'm guessing that it does, but then, does the length function use it, or does it read the BLOB's content? If sqlite keeps track of the size of the BLOB and length doesn't use it, is the size accessible via some other functionality? I'm asking this because I'm wondering if I should implement triggers that set BLOBs' sizes in additional columns, of if I can obtain the sizes dynamically without

Better way to insert blob into MySQL with PHP

由 你说的曾经没有我的故事 提交于 2019-12-21 13:31:42
问题 I am working on a system where I insert files into the database. There are two ways how I am able to insert blob into DB, so I'm curious which one is better. The first is to get the content and then bind parameter of content as a string when inserting: $fp = fopen($tmpName, 'r'); $content = fread($fp, filesize($tmpName)); $content = addslashes($content); fclose($fp); ... $prep_stmt = "INSERT INTO dokumenty (name, size, type, content, autor, poznamka) VALUES (?, ?, ?, ?, ?, ?)"; $stmt =

Better way to insert blob into MySQL with PHP

由 三世轮回 提交于 2019-12-21 13:31:32
问题 I am working on a system where I insert files into the database. There are two ways how I am able to insert blob into DB, so I'm curious which one is better. The first is to get the content and then bind parameter of content as a string when inserting: $fp = fopen($tmpName, 'r'); $content = fread($fp, filesize($tmpName)); $content = addslashes($content); fclose($fp); ... $prep_stmt = "INSERT INTO dokumenty (name, size, type, content, autor, poznamka) VALUES (?, ?, ?, ?, ?, ?)"; $stmt =

Angular2: How to handle a async image (blob) request?

由 扶醉桌前 提交于 2019-12-21 12:27:09
问题 I am trying to request a image via a secured api. At the moment I got the following to work (see all the resources I use below. import { AssetsService } from '../../services/AssetsService'; import { Component } from '@angular/core'; @Component({ templateUrl: 'home.html', }) export class HomePage { public img; constructor( public assets_service: AssetsService ) { } public async ionViewDidEnter() { this.img = await this.assets_service.picture_request('test.png'); } } My view <img [src]="img |

File not downloading with BLOB object in iphone chrome browser

由 泄露秘密 提交于 2019-12-21 12:19:43
问题 I am trying to download the pdf file from server (jsp) using ajax call ,I am getting data in Base 64 format from server ,then converting it into ArrayBuffer and then downloading it with blob object ,below code is working fine for every browser except chrome in iphones even in safari for iphones it is working fine,I don't know whats the issue any help regarding that will be really appreciated function hello(id) { //alert(id); //alert(id); var ln="en"; $.ajax({ type:'post', url:'ajaxurl', data:

When are JavaScript Blob objects garbage collected?

由 三世轮回 提交于 2019-12-21 09:16:20
问题 In modern browsers, it's possible to allocate a large object as a Blob , then request access to it via a URL. This URL will serve the stored object (such as an image's data) elsewhere in the browser. How does the browser know when this URL is no longer needed, and the corresponding Blob data is free to be garbage collected? 回答1: The browser will eventually clear up this resource, however it may be some while (hours or days) before it is removed from memory/disk. If you wish to explicitly

When are JavaScript Blob objects garbage collected?

由 一世执手 提交于 2019-12-21 09:16:07
问题 In modern browsers, it's possible to allocate a large object as a Blob , then request access to it via a URL. This URL will serve the stored object (such as an image's data) elsewhere in the browser. How does the browser know when this URL is no longer needed, and the corresponding Blob data is free to be garbage collected? 回答1: The browser will eventually clear up this resource, however it may be some while (hours or days) before it is removed from memory/disk. If you wish to explicitly

聊聊JS的二进制家族：Blob、ArrayBuffer和Buffer

由 夙愿已清 提交于 2019-12-21 08:37:37
事实上，前端很少涉及对二进制数据的处理，但即便如此，我们偶尔总能在角落里看见它们的身影。 今天我们就来聊一聊前端的二进制家族：Blob、ArrayBuffer和Buffer 概述 Blob: 前端的一个专门用于支持文件操作的二进制对象 ArrayBuffer：前端的一个通用的二进制缓冲区，类似数组，但在API和特性上却有诸多不同 Buffer：Node.js提供的一个二进制缓冲区，常用来处理I/O操作 Blob 我们首先来介绍Blob，Blob是用来支持文件操作的。简单的说：在JS中，有两个构造函数 File 和 Blob, 而File继承了所有Blob的属性。 所以在我们看来，File对象可以看作一种特殊的Blob对象。 在前端工程中，我们在哪些操作中可以获得File对象呢？ 请看： （备注：目前 File API规范的状态为Working Draft） 我们上面说了，File对象是一种特殊的Blob对象，那么它自然就可以直接调用Blob对象的方法。让我们看一看Blob具体有哪些方法，以及能够用它们实现哪些功能 Blob实战 通过window.URL.createObjectURL方法可以把一个blob转化为一个Blob URL，并且用做文件下载或者图片显示的链接。 Blob URL所实现的下载或者显示等功能，仅仅可以在单个浏览器内部进行。而不能在服务器上进行存储

OpenCV return keypoints coordinates and area from blob detection, Python

由 大城市里の小女人 提交于 2019-12-21 07:25:11
问题 I followed a blob detection example (using cv2.SimpleBlobDetector ) and successfully detected the blobs in my binary image. But then I don't know how to extract the coordinates and area of the keypoints. Here are the code for the blob detections: # I skipped the parameter setting part. blobParams = cv2.SimpleBlobDetector_Params() blobVer = (cv2.__version__).split('.') if int(blobVer[0]) < 3: detector = cv2.SimpleBlobDetector(blobParams) else: detector = cv2.SimpleBlobDetector_create
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