ReadCloser

As explained in Go in Action, Second Edition

ReadCloser is a Go interface combining the ability to read data with the ability to close a resource.

ReadCloser is a Go interface that combines Reader and Closer, letting code read from a source and close it when processing finishes. section 10.3 section 2.8.2

Use ReadCloser when an operation must both consume data and finish with resource cleanup.

• Accepts different readable resources through one interface rather than depending on a concrete file or connection type. section 10.3
• Expresses the caller’s required capabilities: reading data and calling Close when the resource is no longer needed. section 2.8.2
• Fits Go’s compositional I/O design alongside Reader, Writer, Closer, WriteCloser, and ReadSeekCloser. section 2.8.2

Processing and closing an input

A processing function can work with a readable resource while retaining the ability to close it safely. The same interface-oriented design supports files and other I/O sources without changing the processing logic. section 10.3 section 2.8.2

Figure 10.1 io.Reader and io.Writer interface composition with multiple package implementations

Shows how Reader and Writer interfaces compose with implementations across packages, placing ReadCloser within Go’s broader I/O abstraction model. section 10.3

How Go in Action, Second Edition covers it

How deep it goes

Defines composition and practical purpose, but stops short of showing a dedicated ReadCloser implementation.

Examples

Uses files and generic I/O processing as concrete contexts for combining reading with resource closure.

What it assumes

Builds on understanding Reader and Closer as separate interfaces before combining their capabilities.

What you can do after

Apply it via Go’s io interfaces to design processing functions that read from and close varied resources.

How it connects

Connects Reader and Closer with Writer, WriteCloser, ReadSeekCloser, files, and composable I/O processing.

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Related concepts

• payloadincludes · A payload is the data, code, or other material carried by or attached to a message, token, system, or operation.
• io.Readerimplements · io.Reader is a Go standard-library interface whose Read method reads bytes into a supplied buffer and reports the number read and any error.
• Closerimplements · io.Closer is a Go interface for resources that can be released or terminated through a Close method that may report an error.
• compositionuses · Composition is a technique for combining simpler functions, components, or operations into a larger structure or behavior.

This explainer was generated by Manning's knowledge graph from the text of Go in Action, Second Edition. The section links point to the parts of the book it draws on.