open

Open a file with a preferred handler

Description

open is a smart tool for reading files:

1. It will read a file from disk or a HTTP(S) endpoints
2. Detect the file type via file extension or HTTP header Content-Type
3. It intelligently writes to stdout

• If stdout is a TTY it will perform any transformations to render to the terminal (eg using inlining images)
• If stdout is a pipe then it will write a byte stream with the relevant data-type

4. If there are no open handlers then it will fallback to the systems default. eg open (on macOS, Linux), open-xdg (X11), etc.

Usage

open filename[.gz]|uri -> <stdout>

Examples

» open https://api.github.com/repos/lmorg/murex/issues -> foreach issue { out "$issue[number]: $issue[title]" }

Detail

File Extensions

Supported file extensions are listed in config under the app and key names of shell, extensions.

Unsupported file extensions are defaulted to generic, *.

Files with a .gz extension are assumed to be gzipped and thus are are automatically expanded.

MIME Types

The Content-Type HTTP header is compared against a list of MIME types, which are stored in config under the app and key names of shell, mime-types.

There is a little bit of additional logic to determine the Murex data-type to use should the MIME type not appear in config, as seen in the following code:

package lang

import (
	"regexp"
	"strings"

	"github.com/lmorg/murex/lang/types"
)

var rxMimePrefix = regexp.MustCompile(`^([-0-9a-zA-Z]+)/.*$`)

// MimeToMurex gets the murex data type for a corresponding MIME
func MimeToMurex(mimeType string) string {
	mime := strings.Split(mimeType, ";")[0]
	mime = strings.TrimSpace(mime)
	mime = strings.ToLower(mime)

	// Find a direct match. This is only used to pick up edge cases, eg text files used as images.
	dt := mimes[mime]
	if dt != "" {
		return dt
	}

	// No direct match found. Fall back to prefix.
	prefix := rxMimePrefix.FindStringSubmatch(mime)
	if len(prefix) != 2 {
		return types.Generic
	}

	switch prefix[1] {
	case "text", "i-world", "message":
		return types.String

	case "audio", "music", "video", "image", "model":
		return types.Binary

	case "application":
		if strings.HasSuffix(mime, "+json") {
			return types.Json
		}
		return types.Generic

	default:
		// Mime type not recognized so lets just make it a generic.
		return types.Generic
	}
}

// MurexToMime returns the default MIME for a given Murex data type.
// The intended use case for this is for GET and POST requests where the body
// is STDIN.
func MurexToMime(dataType string) string {
	return defaultMimes[dataType]
}

HTTP User Agent

open's user agent is the same as get and post and is configurable via config under they app http

» config -> [http]
{
    "cookies": {
        "Data-Type": "json",
        "Default": {
            "example.com": {
                "name": "value"
            },
            "www.example.com": {
                "name": "value"
            }
        },
        "Description": "Defined cookies to send, ordered by domain.",
        "Dynamic": false,
        "Global": false,
        "Value": {
            "example.com": {
                "name": "value"
            },
            "www.example.com": {
                "name": "value"
            }
        }
    },
    "default-https": {
        "Data-Type": "bool",
        "Default": false,
        "Description": "If true then when no protocol is specified (`http://` nor `https://`) then default to `https://`.",
        "Dynamic": false,
        "Global": false,
        "Value": false
    },
    "headers": {
        "Data-Type": "json",
        "Default": {
            "example.com": {
                "name": "value"
            },
            "www.example.com": {
                "name": "value"
            }
        },
        "Description": "Defined HTTP request headers to send, ordered by domain.",
        "Dynamic": false,
        "Global": false,
        "Value": {
            "example.com": {
                "name": "value"
            },
            "www.example.com": {
                "name": "value"
            }
        }
    },
    "insecure": {
        "Data-Type": "bool",
        "Default": false,
        "Description": "Ignore certificate errors.",
        "Dynamic": false,
        "Global": false,
        "Value": false
    },
    "redirect": {
        "Data-Type": "bool",
        "Default": true,
        "Description": "Automatically follow redirects.",
        "Dynamic": false,
        "Global": false,
        "Value": true
    },
    "timeout": {
        "Data-Type": "int",
        "Default": 10,
        "Description": "Timeout in seconds for `get` and `getfile`.",
        "Dynamic": false,
        "Global": false,
        "Value": 10
    },
    "user-agent": {
        "Data-Type": "str",
        "Default": "murex/1.7.0000 BETA",
        "Description": "User agent string for `get` and `getfile`.",
        "Dynamic": false,
        "Global": false,
        "Value": "murex/1.7.0000 BETA"
    }
}

Open Flags

If the open builtin falls back to using the systems default (like open-xdg) then the only thing that gets passed is the path being opened. If the path is stdin then a temporary file will be created. If you want to pass command line flags to open-xdg (for example), then you need to call that command directly. In the case of macOS and some Linux systems, that might look like:

exec open --flags filename

See Also

• * (generic): generic (primitive)
• config: Query or define Murex runtime settings
• exec: Runs an executable
• fexec: Execute a command or function, bypassing the usual order of precedence.
• foreach: Iterate through an array
• get: Makes a standard HTTP request and returns the result as a JSON object
• getfile: Makes a standard HTTP request and return the contents as Murex-aware data type for passing along Murex pipelines.
• openagent: Creates a handler function for open
• out: Print a string to the stdout with a trailing new line character
• post: HTTP POST request with a JSON-parsable return

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This document was generated from builtins/core/open/open_doc.yaml.