全球資訊網中跨終端機交遞系統設計與實作

Abstract

隨著網路的普及，瀏覽全球資訊網已經是一般人上網會做的動作之一，一般人會在全球資訊網上進行購物、搜尋資料、收發電子郵件…等多樣性的應用。在全球資訊網發展初期，單純的瀏覽網頁是主要的應用，所以採用了比較簡單的通訊協定，並無法提供使用者的目前使用狀態以利越來越多樣化的Web應用來使用。不斷的改良之下，網頁伺服器與瀏覽器之間提供一些方法，可以讓網頁伺服器辨識客戶端目前的使用狀態。但是，這些方法的辨識範圍只適用於使用者在同一台機器上，使用者一旦換了終端機，就要重複之前瀏覽的動作，所以目前全球資訊網服務是無法交遞於不同的終端機，這對於越來越受重視的行動計算而言，使用WWW服務也照成了不便。 在這篇論文中，我們設計了一個系統叫做Follow-me Web，此一系統在網頁伺服器和客戶端瀏覽器之間加上一個Follow-me Proxy的three-tier的架構。在不修改終端機上的瀏覽器情況下，Follow-me Proxy可以讓使用者在跨相同或是不同類別的終端機的情況下，交遞使用者在前一終端機所瀏覽的網頁、使用狀態、現在網頁上輸入的資料，讓使用者在跨終端機之後平順的繼續瀏覽。除此之外，Follow-me Proxy也提供了adaptive browsing的功能，使用者可以設定proxy要在客戶端送出的要求，添加哪些CC/PP profile，Web server 便依據CC/PP profile傳回適當的網頁。因此在我們提出的Follow-me Web，我們可以提供跨不同類別終端機的交遞服務和根據設備調整網頁內容的全球資訊網服務。

World-wide Web (WWW) makes the popularity of Internet grows tremendously. Most Internet users access Internet just for browsing the contents of WWW. WWW can provide variety services, such as on-line shopping, data searching, e-mail action, and etc. The initial stage of WWW uses a simple protocol to browse web pages. With the evolution of WWW, we can use some mechanism to help web server to determine client’s using states. On the other hand, as the wireless and terminal technologies advance, user can access Internet anytime, anywhere with any devices. Each device has its own salient characteristics that make it best fit to use in a particular environment. For example a user may prefer using laptop PC in office but PDA or notebook PC in outdoors. However if a user decides to use a new device, he cannot continue browsing on the new device the same WWW session that already exists in the old device, including both HTML document and input text. Instead, he must redo his previous browsing steps and this re-browsing is not only tedious but also waste of time and resources. In this thesis, we propose a Follow-me Web platform that can support inter-device handoff for WWW services. The Follow-me Web platform is a three-tier architecture that consists of web servers, client-side browsers and a Follow-me proxy in between. The Follow-me Proxy can maintain the browsing state of each registered user, and perform device handoff upon receiving a handoff request issued by an authorized user. The proxy can compose a document from the old HTML document and user input together. In addition, the Proxy can use Composite Capability/Preference Profiles (CC/PP) to negotiate with the destined client and adjust the handoff document accordingly. Furthermore users can setup personal preference in the Proxy by an out-of/in-band client application. Upon receiving a handoff request from a user, Proxy appends CC/PP profile to client’s request based on the user’s personal preference. Then web server return adapted web pages depend on CC/PP profiles. Besides, we have plug a COM object in the browser of PCs and use DOM APIs to collect user type-in data. Implementation results show that the Follow-me Web platform can support smooth inter-device handoff and adaptive WWW services smooth.