HS POP3 Library

Emails today have become the default mode of communication and hardly any individual who uses a computer can work without the use email applications. There are various protocols used in emailing while sending and receiving messages and both the server and the client systems require local components with which, these components can access incoming and outgoing emails. If you are a developer and want to create a component for the client systems which can receive email messages via POP3 (Post Office Protocol version 3), then you must certainly consider using HS POP3 Library v.2.0.2 for designing such a component.

HS POP3 Library v.2.0.2 by Hillstone Software is a shareware software library in C programming platform for developing POP3 compatible component for client systems. The incoming transfer of e-mail is implemented over the TCP socket layer in accordance with RFC 1939. The component can even support receiving e-mails over secure POP3 which is used by Gmail over TLS and SSL layers. With the integration of the component developed by this library, the client’s application will be able to receive basic text and headers of e-mails, support user authentication, delete messages and track the statistics. If there are attachments in the mail message in MIME v.1.0 base 64 format, then the application will be able to extract those binary file attachments. The HS POP3 protocol has a modular design due to which, it can be ported to any environment without getting into much complexities. This software library interfaces with HS Sock library at the ground interface layers for providing transport services via TCP.

HS POP3 Library v.2.0.2 is overall, a high utility package with fully functional and comprehensive set of features for implementing the POP3 service on client’s system, leading it to score three and a half rating points out of five.

HS POP3 is a software library in C (supplied with full source code) implements the client side of Post Office Protocol Version 3 (POP3) over TCP socket layer according to RFC 1939. Among other features, the library supports user authentication, reception of basic internet headers and text, message deletion and statistics
HS POP3 supports secure POP3 over TLS / SSL using two methods: POP3S (used by Gmail) and RFC 2595
HS POP3 supports extracting binary file attachments in MIME v1.0 base64 format.
The user application calls HS POP3 initialisation function supplying pointers to callback functions in user code for memory amd timer management and for reporting POP3 events to user.
To receive email messages from any POP3 RFC1939 compliant server, the user application calls HsPop3GetMail function, specifying mail server name or IP address and login user name and password.
HS POP3 library then resolves the server name, connects to it, receives and message scan list. according to RFC1939 standard. Once HS POP3 has a unique message ID from the server, it reports this message ID to user application via callback function. The user application returns a specific value if it wants to receive this message. At this point HS POP3 will request necessary amount of memory for the message and will receive complete message into the buffer. Once message is received, the user code is notified with a callback and a message structure, containing full message pointer, message length, start of text pointer, length of headers and separate parsed out header information: from field, date field, message id field and subject field. This process is repeated until all messages are received. HS POP3 library can also delete messages from server if this option is specified.
Modular design makes it easy to port HS POP3 protocol module to any environment. HS POP3 internally at a lower layer interfaces to HS Sock library which provides TCP transport services.