API 的歷史：應用程式介面的演變

應用程式介面 (API) 是現代軟體開發不可或缺的一部分，可實現不同應用程式、服務和系統之間的連接和通訊。多年來，API 已從簡單的內部工具轉變為網路的支柱，推動著從社群媒體整合到金融交易的一切。

本文將追溯 API 從誕生到其在當今數位經濟中發揮關鍵作用的歷史。

早期： API 的基礎（1960 年代-1980 年代）
子程式和函式庫的誕生
API 的起源可以追溯到 20 世紀 60 年代計算的早期，伴隨著子程式和軟體庫的發展。子例程是可重複使用的程式碼區塊，開發人員可以在程式中呼叫它們，從而減少冗餘並提高效率。這些可重複使用程式碼區塊為 API 的概念奠定了基礎，讓軟體元件進行內部通訊。

隨著軟體系統複雜性的增加，對與系統功能互動的有組織和標準化的方式的需求也隨之增加。軟體庫出現了，提供了可以被程式其他部分存取的預先建置功能。這些庫透過早期的內部 API 訪問，允許開發人員利用現有功能，而無需重寫程式碼。

模組化程式設計的概念
到了 20 世紀 70 年代和 80 年代，模組化程式設計的想法開始流行。在模組化程式設計中，軟體被設計為獨立的單元或模組，每個單元或模組負責特定的任務。這些模組使用預先定義的介面相互通信，這是 API 的早期形式。

網路系統的興起：分散式運算 API（1980 年代-1990 年代）

隨著電腦開始透過網路互連，系統在不同機器之間進行通訊的需求變得至關重要。這一轉變標誌著 API 發展的關鍵轉折點。
遠端過程呼叫 (RPC)

20 世紀 80 年代，遠端過程呼叫 (RPC) 被開發出來，允許軟體在網路中的另一台電腦上執行過程。這個概念是朝著我們今天所知的 API 邁出的重要一步，因為它使不同的機器能夠以標準化的方式進行交互，從而使分散式計算成為可能。

CORBA 和 COM
1990 年代，CORBA（通用物件請求代理架構）和 COM（元件物件模型）的出現徹底改變了軟體元件在分散式環境中進行通訊的方式。 CORBA 允許以不同程式語言編寫並在不同作業系統上運行的應用程式進行通信，而 COM 則允許跨應用程式重複使用軟體元件。

然而，這些早期的 API 系統非常複雜，而且實作起來往往具有挑戰性，因此需要尋找更簡單、更靈活的解決方案。
網路時代：API 與網際網路（1990 年代-2000 年代）
20 世紀 90 年代萬維網的興起為 API 的構思和使用方式帶來了巨大的轉變。網路為透過網路連接不同的應用程式和服務開闢了新的可能性，而 API 對於實現這種互連性至關重要。

SOAP 的出現
20 世紀 90 年代末，簡單物件存取協定 (SOAP) 作為一種用於在 Web 服務中交換結構化資訊的協定而出現。基於 SOAP 的 API 允許不同的應用程式透過 Web 進行通信，通常使用 XML 來建構資料。雖然 SOAP 提供了一種實現跨平台互動的方法，但它通常被視為重量級且過於複雜。

早期公用 API
2000 年代初期，公共 API 興起，公司開始公開其內部功能以供外部使用。第一個值得注意的例子是 Salesforce，它於 2000 年推出了一個 API，允許開發人員存取其 CRM 平台，標誌著 API 成為核心業務策略時代的開始。
API 革命：REST 與雲端（2000 年代至今）
2000 年代，隨著 REST（表述性狀態傳輸）的引入，API 設計發生了一場革命，簡化了應用程式透過網路進行通訊的方式。

RESTful APIs
In 2000, Roy Fielding introduced the concept of REST in his doctoral dissertation. RESTful APIs leveraged existing web standards, primarily HTTP, and were designed to be simpler and more lightweight than their predecessors, such as SOAP. REST allowed developers to build APIs that could easily be consumed by any client capable of sending HTTP requests, making it easier to integrate systems over the web.
REST quickly gained popularity, becoming the dominant API design model for web-based applications. Its stateless nature and simplicity led to widespread adoption by companies like Twitter, Facebook, and Google, which began offering public APIs to allow developers to build applications on top of their platforms.

The Rise of Cloud Computing
The rise of cloud computing further accelerated the demand for APIs. Cloud platforms like Amazon Web Services (AWS), Google Cloud, and Microsoft Azure exposed APIs that allowed developers to interact with cloud services programmatically. APIs became the de facto method for integrating cloud services, from storage to computing power.

APIs in the Modern Era: Microservices and Beyond
In the 2010s, the rise of microservices architecture transformed the way applications were built. Instead of monolithic applications, systems were broken down into smaller, loosely coupled services that communicated through APIs. This architecture allowed for more scalable and flexible applications, where different services could be developed, deployed, and scaled independently.

GraphQL
In 2015, Facebook introduced GraphQL, a new query language for APIs. Unlike REST, where each endpoint returns a fixed structure, GraphQL allowed clients to request exactly the data they needed, reducing over-fetching and under-fetching of data. This flexibility made it particularly appealing for complex applications, such as those involving multiple client types (e.g., web, mobile).

API Ecosystems
APIs are now at the heart of many digital ecosystems. Platforms like Stripe, Twilio, and Slack have built their entire business models around providing APIs that developers can use to build payment systems, communications platforms, and integrations.

API Gateways and Management
As APIs have become more critical to business operations, the need for managing them effectively has grown. API gateways and management tools have emerged to handle concerns like rate limiting, authentication, monitoring, and security. Companies use tools like Kong, Apigee, and AWS API Gateway to manage the complex interactions of APIs in large-scale systems.

The Future of APIs
As we move into the future, the role of APIs will continue to expand with trends such as:

1. Serverless Architectures: APIs are playing a key role in the rise of serverless computing, where developers rely on cloud services to automatically manage infrastructure, scaling, and maintenance.
2. AI and Machine Learning APIs: With AI and machine learning becoming more prominent, APIs like Google’s TensorFlow and OpenAI’s GPT are making these technologies accessible to developers.
3. API-First Development: More organizations are adopting an API-first approach to software development, where the API is treated as the core of the application, ensuring that it is well-designed, scalable, and easily consumable.

Conclusion
The history of APIs is a journey of innovation, from the early days of internal software libraries to the modern web-based, cloud-integrated, and microservice-driven APIs we use today. APIs have become the backbone of the internet, driving innovation, enabling new business models, and powering everything from social media apps to financial transactions.
As technology evolves, APIs will continue to shape how we build, integrate, and scale software systems, making them a crucial aspect of the future of digital transformation.

以上是API 的歷史：應用程式介面的演變的詳細內容。更多資訊請關注PHP中文網其他相關文章！