How to Download and Save Go File Using net/http Package in Go
Is there a way to download a large file using Go that will store the content directly into a file instead of storing it all in memory before writing it to a file? Because the file is so big, storing it all in memory before writing it to a file is going to use up all the memory.
download go file
The answer selected above using io.Copy is exactly what you need, but if you are interested in additional features like resuming broken downloads, auto-naming files, checksum validation or monitoring progress of multiple downloads, checkout the grab package.
I also think it's nice to have a progress indicator, especially for larger files. So I want to throw in my two cents for a solution to this problem while implementing a simple progress indicator.(Most error handling also omitted for brevety).
It lets you interact with remote systems by making requests to those systems and retrieving and displaying their responses to you. This can be files, images, etc. but it can also be an API call. curl supports over 20 protocols, including HTTP, HTTPS, SCP, SFTP, and FTP. And arguably, due to its superior handling of Linux pipes, curl can be more easily integrated with other commands and scripts.
How to download and install Go programming language
Go tutorial: Getting started with Hello, World
Go grab: A package for downloading files in Go
Download Go source code from GitHub
Go net/http: A package for making HTTP requests and downloading files
How to download and run Go binaries on Windows
Go modules: How to manage dependencies and download packages
Download Go documentation and tools
How to download and use Go playground
Go io/ioutil: A package for reading and writing files in Go
How to download and install Go on Linux
Go os: A package for interacting with the operating system and files
How to download and install Go on Mac
Go archive/tar: A package for creating and extracting tar files in Go
How to download and unzip Go zip files
Go archive/zip: A package for creating and extracting zip files in Go
How to download and install Go extensions for Visual Studio Code
Go compress/gzip: A package for compressing and decompressing gzip files in Go
How to download and install Go tools like gofmt, golint, and govet
Go encoding/json: A package for encoding and decoding JSON files in Go
How to download and parse CSV files in Go
Go encoding/csv: A package for reading and writing CSV files in Go
How to download and parse XML files in Go
Go encoding/xml: A package for encoding and decoding XML files in Go
How to download and parse YAML files in Go
Go gopkg.in/yaml.v2: A package for reading and writing YAML files in Go
How to download and parse TOML files in Go
Go github.com/BurntSushi/toml: A package for encoding and decoding TOML files in Go
How to download and parse INI files in Go
Go gopkg.in/ini.v1: A package for loading INI files in Go
How to download and parse PDF files in Go
Go github.com/unidoc/unipdf: A package for creating and processing PDF files in Go
How to download and parse Excel files in Go
Go github.com/360EntSecGroup-Skylar/excelize: A package for reading and writing Excel files in Go
How to download and parse Word files in Go
Go github.com/nguyenthenguyen/docx: A package for creating and manipulating Word documents in Go
How to download and parse PowerPoint files in Go
Go github.com/360EntSecGroup-Skylar/pptx: A package for reading and writing PowerPoint files in Go
How to download and parse Markdown files in Go
Go github.com/gomarkdown/markdown: A package for rendering Markdown documents in various formats in Go
How to download and parse HTML files in Go
Go net/html: A package for parsing HTML documents in Go
How to download images from the web in Go
Go image: A package for manipulating images in various formats in Go
How to download videos from the web in Go
goav - Golang bindings for FFmpeg. A comprehensive set of bindings that allow you to manipulate video, audio, codecs, etc. using the FFmpeg libraries.
For tar and zip files, I find it more useful to simply use the wget command, especially since I can pair it with the tar -xzvf commands. However, for image files, the net/http package is very capable. However, there is more community involvement going on at present to develop a more robust, concurrent download package.
These files contain the core GO ontology in two formats, OBO and OWL-RDF/XML. This view includes relationships not in the filtered version of GO including has_part and occurs_in. Many of these relationships may not be safe for propagating annotations across, so this version should not be used with legacy GO tools. This version excludes relationships to external ontologies.
Many GO classes have been cross-referenced (mapped) to a number of external classification systems. The cross-references of external classification systems to GO page contains more information and links to the cross-reference2GO files.
If a module might be depended on by other modules, these rules must be followedso that the go command can find and download the module. There are alsoseveral lexical restrictions on characters allowed inmodule paths.
The go command starts by searching the build list formodules with paths that are prefixes of the package path. For example, if thepackage example.com/a/b is imported, and the module example.com/a is in thebuild list, the go command will check whether example.com/a contains thepackage, in the directory b. At least one file with the .go extension mustbe present in a directory for it to be considered a package. Buildconstraints are not applied for thispurpose. If exactly one module in the build list provides the package, thatmodule is used. If no modules provide the package or if two or more modulesprovide the package, the go command reports an error. The -mod=mod flaginstructs the go command to attempt to find new modules providing missingpackages and to update go.mod and go.sum. The go get and go mod tidy commands do this automatically.
For each entry in the GOPROXY list, the go command requests the latestversion of each module path that might provide the package (that is, each prefixof the package path). For each successfully requested module path, the gocommand will download the module at the latest version and check whether themodule contains the requested package. If one or more modules contain therequested package, the module with the longest path is used. If one or moremodules are found but none contain the requested package, an error isreported. If no modules are found, the go command tries the next entry in theGOPROXY list. If no entries are left, an error is reported.
A module is defined by a UTF-8 encoded text file named go.mod in its rootdirectory. The go.mod file is line-oriented. Each line holds a singledirective, made up of a keyword followed by arguments. For example:
The go.mod file is designed to be human readable and machine writable. Thego command provides several subcommands that change go.mod files. Forexample, go get can upgrade or downgrade specific dependencies.Commands that load the module graph will automaticallyupdate go.mod when needed. go mod edit can perform low-level edits. Thegolang.org/x/mod/modfilepackage can be used by Go programs to make the same changes programmatically.
A go.mod file is required for the main module, and forany replacement module specified with a local file path.However, a module that lacks an explicit go.mod file may still berequired as a dependency, or used as a replacementspecified with a module path and version; see Compatibility with non-modulerepositories.
If the module path appears in a require directive and is not replaced, orif the module paths appears on the right side of a replace directive,the go command may need to download modules with that path, and someadditional requirements must be satisfied.
When the go command retrieves deprecation information for a module, it loadsthe go.mod file from the version matching the @latest versionquery without considering retractions orexclusions. The go command loads the list ofretracted versions from the same go.mod file.
A require directive declares a minimum required version of a given moduledependency. For each required module version, the go command loads thego.mod file for that version and incorporates the requirements from thatfile. Once all requirements have been loaded, the go command resolves themusing minimal version selection (MVS) to producethe build list.
A replace directive replaces the contents of a specific version of a module,or all versions of a module, with contents found elsewhere. The replacementmay be specified with either another module path and version, or aplatform-specific file path.
If the path on the right side of the arrow is an absolute or relative path(beginning with ./ or ../), it is interpreted as the local file path to thereplacement module root directory, which must contain a go.mod file. Thereplacement version must be omitted in this case.
Conceptually, MVS operates on a directed graph of modules, specified withgo.mod files. Each vertex in the graph represents amodule version. Each edge represents a minimum required version of a dependency,specified using a requiredirective. The graph may be modified by excludeand replace directives in the go.mod file(s) of the mainmodule(s) and by replace directives in the go.work file.
MVS visits and loads the go.mod file for each of the module versionshighlighted in blue. At the end of the graph traversal, MVS returns a build listcontaining the bolded versions: A 1.2, B 1.2, C 1.4, and D 1.2. Note that higherversions of B and D are available but MVS does not select them, since nothingrequires them.
If the main module is at go 1.17 or higher, the modulegraph used for minimal versionselection includes only the immediaterequirements for each module dependency that specifies go 1.17 or higher inits own go.mod file, unless that version of the module is also (transitively)required by some other dependency at go 1.16 or below. (The transitivedependencies of go 1.17 dependencies are pruned out of the module graph.)
Since a go 1.17 go.mod file includes a requiredirective for every dependency needed to build anypackage or test in that module, the pruned module graph includes all of thedependencies needed to go build or go test the packages in any dependencyexplicitly required by the main module. A module that isnot needed to build any package or test in a given module cannot affect therun-time behavior of its packages, so the dependencies that are pruned out ofthe module graph would only cause interference between otherwise-unrelatedmodules.
The go.sum file recorded by go mod tidy fora module by default includes checksums needed by the Go version one below theversion specified in its go directive. So a go 1.17module includes checksums needed for the full module graph loaded by Go 1.16,but a go 1.18 module will include only the checksums needed for the prunedmodule graph loaded by Go 1.17. The -compat flag can be used to override thedefault version (for example, to prune the go.sum file more aggressively in ago 1.17 module).
If all imported packages can be found without loading the module graph, thego command then loads the go.mod files for only the modules containingthose packages, and their requirements are checked against the requirements ofthe main module to ensure that they are locally consistent. (Inconsistencies canarise due to version-control merges, hand-edits, and changes in modules thathave been replaced using local filesystem paths.)
A workspace can be declared in a go.work file that specifiesrelative paths to the module directories of each of the modules in the workspace.When no go.work file exists, the workspace consists of the single modulecontaining the current directory.
A command determines whether it is in a workspace context by first examiningthe GOWORK environment variable. If GOWORK is set to off, the command will bein a single-module context. If it is empty or not provided, the commandwill search the current working directory, and then successive parent directories,for a file go.work. If a file is found, the command will operate in theworkspace it defines; otherwise, the workspace will include only the modulecontaining the working directory.If GOWORK names a path to an existing file that ends in .work,workspace mode will be enabled. Any other value is an error. You can use thego env GOWORK command to determine which go.work file the go commandis using. go env GOWORK will be empty if the go command is not in workspacemode.
The go command provides several subcommands for manipulating go.work files.go work init creates new go.work files. go work use adds module directories tothe go.work file. go work edit performs low-leveledits. Thegolang.org/x/mod/modfilepackage can be used by Go programs to make the same changes programmatically.