Reprinted from: http://blog.chinaunix.net/uid-20146676-id-1733417.html
Schmeilin's "Theory and Application of Computer Supported Collaborative Work" explains Borker, Agent and Proxy as follows:
In order to improve the architecture of the Internet, various agents such as Borker, Agent and Proxy can be used comprehensively. Agent is an entity with control function, it receives information, then processes the information according to its own knowledge, rules and control logic, and then forwards the information. Agent usually exists as an element and serves as a whole. In the information flow, Agent acts as an intermediate processing component, which receives operation instructions, and specifies operation steps according to its own knowledge, rules, and control logic to complete the required operation. function, and then peer-to-peer output, which is the first role of the agent. Agent has strong expressive ability, which means that agents can communicate through ACL, such as exchanging data, logic information and instructions, which is a remarkable feature of Agent. Agent is very similar to the concept of object in object-oriented: the internal data structure and algorithm of Agent are also hidden to the outside world, and it communicates with the outside world through a message-based interface. The difference between Agent and object is mainly reflected in the interface language. In object-oriented programming, when objects communicate with each other, different objects can understand the same message differently; in the agent mode, the common language is used for communication between agents, and its semantics is independent of the specific agent, so the agent The second role of the charging intermediate processing component is that it represents an entity with a specific interface and provides a public interface to the outside world, which is the key to solving resource heterogeneity.
Agent has publicity (commonality, Agent communication language is independent of Agent), authenticity (veracity, Agent must truthfully and frankly announce its own functions), autonomy (autonomy, one Agent cannot force another Agent to perform a certain task, unless The latter announces that it has this function) and mandatory (commitment, if the Agent announces one of its own services, when it receives a request to execute the service, it must receive the request and execute the service). The publicity of Agent makes it very suitable for solving the problem of resource heterogeneity. It can be seen from its last three characteristics that Agent is very suitable for dynamic and scalable environment.
Broker can easily provide mutual awareness (awareness) between agents. We know that the Internet is a dynamic and shrinkable environment, which means that the representative of the entity, the Agent, should be able to dynamically increase and decrease. Borker provides a place for agents to register, which provides the most basic visibility: agents can be aware of the existence of each other, and further, in a collaborative application environment, the actions of each entity should have an impact on other entities . This means that two Agents must conduct necessary negotiation before they can actually interact, and they must
also . When there are many agents, each agent must contain the code for negotiation and cooperative control with all other agents, which is not only expensive, but also complicated to implement. As a result, centralized collaborative control is possible through Borker, providing higher levels of mutual visibility.
The communication between the browser and the HTTP server is carried out through the standard HTTP protocol, and the function of the HTTP protocol is limited. Therefore, a proxy is introduced between the browser and the HTTP server. Proxy acts as both an HTTP server and an HTTP client. We extend the HTTP protocol between Porxy and the HTTP server to enhance the communication function between the client and the server, which is transparent to the browser.
Agent has publicity (commonality, Agent communication language is independent of Agent), authenticity (veracity, Agent must truthfully and frankly announce its own functions), autonomy (autonomy, one Agent cannot force another Agent to perform a certain task, unless The latter announces that it has this function) and mandatory (commitment, if the Agent announces one of its own services, when it receives a request to execute the service, it must receive the request and execute the service). The publicity of Agent makes it very suitable for solving the problem of resource heterogeneity. It can be seen from its last three characteristics that Agent is very suitable for dynamic and scalable environment.
Broker can easily provide mutual awareness (awareness) between agents. We know that the Internet is a dynamic and shrinkable environment, which means that the representative of the entity, the Agent, should be able to dynamically increase and decrease. Borker provides a place for agents to register, which provides the most basic visibility: agents can be aware of the existence of each other, and further, in a collaborative application environment, the actions of each entity should have an impact on other entities . This means that two Agents must conduct necessary negotiation before they can actually interact, and they must
also . When there are many agents, each agent must contain the code for negotiation and cooperative control with all other agents, which is not only expensive, but also complicated to implement. As a result, centralized collaborative control is possible through Borker, providing higher levels of mutual visibility.
The communication between the browser and the HTTP server is carried out through the standard HTTP protocol, and the function of the HTTP protocol is limited. Therefore, a proxy is introduced between the browser and the HTTP server. Proxy acts as both an HTTP server and an HTTP client. We extend the HTTP protocol between Porxy and the HTTP server to enhance the communication function between the client and the server, which is transparent to the browser.