blog(new):add a blog that supports resume upload

add a blog that introduces resume upload and continuous transfer features

frontend/content/blog/resumable-transfers-en.mdx

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+---
+title: "PrivyDrop's New Milestone: Resumable Transfers to End Large File Transfer Anxiety"
+description: "PrivyDrop gets a major update! The new resumable transfer feature lets you fearlessly handle network interruptions and easily transfer gigabyte-scale files. Learn how it works and how we perfectly combine ultimate reliability with privacy and security."
+date: "2025-08-01"
+author: "david bai"
+cover: "/blog-assets/privydrop-resumable-transfer.jpg"
+tags: ["New Feature", "Resumable Transfers", "File Transfer", "Privacy", "Open Source"]
+status: "published"
+---
+
+![](/blog-assets/privydrop-resumable-transfer.jpg)
+
+## Introduction: The Final Mile from "Usable" to "Enjoyable"
+
+In previous articles, we introduced [<u>**the open-source spirit of PrivyDrop**</u>](/blog/privydrop-open-source-en) and the core technology behind it, [<u>**WebRTC**</u>](/blog/webrtc-file-transfer-en). We successfully created a secure and private file-sharing tool based on peer-to-peer (P2P) technology.
+
+However, we know that a tool's value lies not just in being "usable," but in how "enjoyable" it is in the real world. Imagine this scenario: you're at a coffee shop with unstable Wi-Fi, sending an urgent 4GB rendered video file to a client. The progress bar slowly creeps to 95%, and then... the network drops.
+
+We've all felt that gut-wrenching frustration of failure at the last moment.
+
+Today, we are proud to announce that PrivyDrop has completed that final mile from "usable" to "enjoyable." We are officially launching the **resumable transfers** feature, designed to put an end to your "transfer anxiety" for good.
+
+## The Core Weapon: How Do Smart Resumable Transfers Work?
+
+Before diving into how to use it, you might be wondering: how does PrivyDrop "remember" the transfer progress?
+
+### Unveiling the Principle: How is the "Memory" of Resumable Transfers Achieved?
+
+We like to compare the process to assembling a giant digital jigsaw puzzle:
+
+1.  **Exchanging the "Blueprint"**: Before the transfer begins, the sender first sends a "blueprint" of the file (i.e., metadata containing the filename, total size, chunk information, etc.) to the receiver. The receiver uses this blueprint to get a complete picture of the "puzzle" ahead of time.
+
+2.  **Receiving "Puzzle Pieces" by Number**: The file is divided into countless small data chunks, which are numbered and transferred sequentially. As the receiver gets each piece, they place it in its correct position on the "blueprint."
+
+3.  **The "Smart Inventory" After an Interruption**: When the transfer is unexpectedly interrupted, the receiver holds onto all the "puzzle pieces" they've already collected. When the connection is re-established, the receiver takes out the "blueprint," does an inventory check, and tells the sender: "I already have pieces #1 to #5000. Please start sending from #5001."
+
+This "smart inventory and request" mechanism is the core of our resumable transfer technology. It eliminates the need to start from scratch, dramatically improving the efficiency and reliability of large file transfers.
+
+### A Practical Guide: How to Use Resumable Transfers Correctly
+
+Now, let's walk through how to master this powerful feature in practice.
+
+**Step 1: Enable "Safe Mode" (Receiver)**
+
+Before receiving a file, you must click **"Set Save Directory"**. This step is crucial. It tells PrivyDrop, "Please prepare a safe home for the incoming file." Only then will the resumable transfer feature be activated.
+
+**Step 2: When an Interruption Occurs**
+
+Network fluctuations, accidentally closing the tab, your computer going to sleep... when interruptions inevitably happen, stay calm. Your file progress is safe.
+
+**Step 3: Lock in Your Progress (The Key Action)**
+
+To **lock in and securely save** the file fragments you've already received, you need to **refresh or close the current page**.
+
+This is where PrivyDrop's carefully designed **Exit Protection Mechanism** comes into play. Normally, if a page with an active download is suddenly closed, the browser might discard the incomplete temporary file, leading to data loss.
+
+We've engineered a solution: when you refresh or close the page, PrivyDrop's code intercepts this action. Instead of letting the browser abandon the file, it acts like a responsible archivist, **gracefully closing the disk write stream to finalize and save the data already received**. This action transforms the temporary file into a stable "save point" ready for the next transfer attempt.
+
+**Step 4: Seamless Resumption**
+
+Now, simply have the sender and you re-enter the same room and start the transfer again. You'll magically see the progress bar jump to where it left off and continue its steady march forward. That's the magic of resumable transfers!
+
+## From "Single Task" to "Continuous Collaboration": Meet Your Private Data Channel
+
+Having solved the reliability of large file transfers, we also wanted to make the exchange process more intuitive. Traditional tools operate on a "send one, start over" model. PrivyDrop, however, provides a **persistent private data channel**.
+
+Once two parties are connected, the room becomes your exclusive "virtual office." You can share content continuously without repeating the "create room, share link" cycle every time.
+
+Imagine this workflow:
+
+1.  You send a text description via the clipboard.
+2.  After the other person receives it, you drag and drop a design mockup (a PNG file).
+3.  Once the mockup is sent, you immediately follow up by dragging in a folder containing all the assets.
+
+The entire process is fluid and natural, just like talking to a colleague sitting next to you. This "continuous transfer" feature elevates PrivyDrop from a "one-time file transfer tool" to a "**lightweight, highly private, real-time collaboration space**."
+
+## When "Reliability" Meets "Privacy"
+
+You might be wondering if these powerful new features come at the cost of PrivyDrop's privacy.
+
+The answer is: **absolutely not**. All our feature development is built on a foundation of privacy and security.
+
+- **Resumable Transfers & End-to-End Encryption**: We want to be clear: even the fragmented file chunks used for resumable transfers are transmitted with the same end-to-end encryption (DTLS protocol) as a complete file, directly between browsers. The server can never inspect, reassemble, or store any of the content.
+
+- **"Unlimited Size" x "Resumable Transfers"**: This is our proud "golden combination." "No file size limits" is our promise, and "resumable transfers" is the insurance that lets us keep it. Now you can truly use PrivyDrop to back up an entire hard drive or transfer massive datasets without fear of losing your progress.
+
+- **The Confidence of Open Source**: We don't just promise security; we show our work. Every line of code for our resumable and continuous transfer features is publicly available in our [<u>**GitHub repository**</u>](https://github.com/david-bai00/PrivyDrop), open for review and scrutiny by developers worldwide.
+
+## Conclusion: We Invite You to a "Fearless" Transfer
+
+PrivyDrop is no longer just a tool; it's becoming the trustworthy partner you can rely on for your personal and professional data, fearless of any interruption.
+
+Don't hesitate! Visit [<u>**privydrop.app**</u>](https://www.privydrop.app) right now, find the largest file on your computer, and **intentionally refresh the page mid-transfer**. Experience for yourself that reassuring feeling of "recovering the lost."
+
+If you're as passionate as we are about building ultra-secure and reliable tools, please give us a Star on [<u>**GitHub**</u>](https://github.com/david-bai00/PrivyDrop). Your support is our greatest motivation!

frontend/content/blog/resumable-transfers-zh.mdx

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+---
+title: "PrivyDrop 新里程碑：断点续传，让大文件传输告别焦虑"
+description: "PrivyDrop 迎来重大更新！全新的断点续传功能，让你无惧网络中断，轻松传输G级别大文件。了解它是如何工作的，以及我们如何将极致的可靠性与隐私安全完美结合。"
+date: "2025-08-01"
+author: "david bai"
+cover: "/blog-assets/privydrop-resumable-transfer.jpg"
+tags: ["新功能", "断点续传", "文件传输", "隐私安全", "开源"]
+status: "published"
+---
+
+![](/blog-assets/privydrop-resumable-transfer.jpg)
+
+## 引言：从“能用”到“好用”的最后一公里
+
+在之前的文章中，我们介绍了 [<u>**PrivyDrop 的开源初心**</u>](/blog/privydrop-open-source-zh) 以及其背后的核心技术 [<u>**WebRTC**</u>](/blog/webRTC-file-transfer-zh)。我们成功地实现了一个基于点对点（P2P）技术的安全、私密文件分享工具。
+
+但是，我们深知一个工具的价值不仅在于它“能用”，更在于它在真实世界中的“好用”程度。想象一下这个场景：你正在用咖啡店那不太稳定的 Wi-Fi，给客户传输一份紧急的 4GB 视频渲染文件，就在进度条缓慢爬升到 95% 的时候，网络闪断了……
+
+那种功亏一篑的挫败感，我们感同身受。
+
+今天，我们自豪地宣布，PrivyDrop 走完了从“能用”到“好用”的最后一公里。我们正式推出**断点续传**功能，旨在彻底终结你的“传输焦虑”。
+
+## 核心武器——智能断点续传，如何工作？
+
+在深入了解如何使用它之前，你可能想知道：PrivyDrop 是如何“记住”传输进度的？
+
+### 原理揭秘：断点续传的“记忆”是如何实现的？
+
+我们将这个过程比作拼凑一幅巨大的数字拼图：
+
+1.  **交换“蓝图”**：在传输开始前，发送方会先将一份文件的“蓝图”（即元数据，包含文件名、总大小、分块信息等）发送给接收方。接收方根据这份蓝图，提前了解整个“拼图”的全貌。
+
+2.  **按编号接收“拼图”**：文件被分割成无数个小数据块，并按顺序编号进行传输。接收方每收到一块，就将其安放到“蓝图”上对应的位置。
+
+3.  **中断后的“智能盘点”**：当传输意外中断后，接收方会保管好已经收到的所有“拼图碎片”。当连接重新建立时，接收方会拿出“蓝图”进行盘点，然后告诉发送方：“我已经有第 1 到第 5000 号拼图了，请直接从第 5001 号开始发。”
+
+这个“智能盘点和请求”的机制，就是断点续传技术的核心。它避免了从头开始的重复工作，极大地提升了大文件传输的效率和可靠性。
+
+### 实战指南：如何正确使用断点续传？
+
+现在，让我们看看在实际操作中如何驾驭这一强大功能。
+
+**第一步：开启“安全模式” (接收方)**
+
+在接收文件前，请务必点击 **“设置保存目录”**。这一步至关重要，它等于告诉 PrivyDrop：“请为即将到来的文件准备一个安全的家”。只有这样，断点续传功能才会被激活。
+
+**第二步：当中断发生时**
+
+网络波动、手滑关闭页面、电脑意外休眠……当中断不可避免地发生时，请保持冷静，你的文件进度是安全的。
+
+**第三步：锁定进度 (关键操作)**
+
+为了**锁定并安全保存**已接收的文件片段，你需要**刷新或关闭当前页面**。
+
+这里正是 PrivyDrop 精心设计的**退出保护机制 (Exit Protection Mechanism)** 发挥作用的地方。通常情况下，若一个有活跃下载的页面被突然关闭，浏览器可能会直接丢弃未完成的临时文件，导致数据丢失。
+
+而我们为此设计了解决方案：当你刷新或关闭页面时，PrivyDrop 的代码会拦截这个行为，它不会任由浏览器放弃文件，而是像一个负责任的档案管理员，**优雅地关闭磁盘写入流，将已经接收的数据进行最终确认和保存**。这个动作，确保了临时文件被转化为一个稳定、可供下次续传的“存档点”。
+
+**第四步：无缝续传**
+
+现在，只需让发送方和你重新进入同一个房间，再次发起传输。你会神奇地发现，进度条会瞬间跳到之前中断的位置，然后继续稳步前进。这就是断点续传的魔力！
+
+## 从“单次任务”到“持续协作”：认识你的私人数据通道
+
+解决了大文件传输的可靠性，我们还想让文件交换的过程更符合直觉。传统的工具是“发完一个，从头再来”，而 PrivyDrop 提供的是一个**持久的私人数据通道**。
+
+一旦双方建立连接，这个房间就成了一个只属于你们的“虚拟办公室”。你可以连续不断地分享内容，而无需每次都重复“创建房间-分享链接”的步骤。
+
+想象一下这个工作流：
+
+1.  你通过剪贴板发一段文字说明。
+2.  对方接收后，你直接拖入一个设计稿（PNG 文件）。
+3.  设计稿传完，你紧接着拖入一个包含所有素材的文件夹。
+
+整个过程行云流水，就像在和坐你旁边的同事对话一样自然。这个“连续传输”特性，将 PrivyDrop 从一个“一次性文件传输工具”提升为“**轻量级、高私密的实时协作空间**”。
+
+## 当“可靠”与“隐私”相遇
+
+你可能会问，这些强大的新功能是否会牺牲 PrivyDrop 的隐私性？
+
+答案是：**绝对不会**。我们的所有功能开发，都建立在隐私安全的基石之上。
+
+- **断点续传与端到端加密**：我们明确指出，即便是被拆分的、用于断点续传的文件块，在传输时依然经过了与完整文件相同的端到端加密（DTLS 协议），直接在浏览器之间传输。服务器永远无法窥探、拼接或存储其中的任何内容。
+
+- **“无限大小” x “断点续传”**：这是我们引以为傲的“黄金组合”。“无文件大小限制”是我们的承诺，“断点续传”则是我们兑现这个承诺的保险。现在，你可以真正放心地用它来备份整个硬盘，或者传输巨大的数据集，而无需担心前功尽弃。
+
+- **开源的自信**：我们不仅承诺安全，更展示代码。断点续传和连续传输的每一行实现，都公开在我们的 [<u>**GitHub 仓库**</u>](https://github.com/david-bai00/PrivyDrop) 中，欢迎全球的开发者一同审阅和监督。
+
+## 结论：邀请你来一次“无畏”的传输
+
+PrivyDrop 不再只是一个工具，它正在成为你处理个人和工作数据时，那个最值得信赖的、无惧任何意外的伙伴。
+
+别再犹豫了！立即访问 [<u>**privydrop.app**</u>](https://www.privydrop.app)，找一个你电脑里最大的文件，**故意在传输中途刷新页面**，亲身体验一下那份“失而复得”的安心感。
+
+如果你和我们一样，对打造极致安全、可靠的工具充满热情，请在 [<u>**GitHub**</u>](https://github.com/david-bai00/PrivyDrop) 上给我们一个 Star，你的支持是我们前进的最大动力！