Adding http[s] transpiler (Fixes #169)

Author: James Brundage

Transpilers/Protocols/Http.Protocol.psx.ps1

@@ -0,0 +1,166 @@
+<#
+.SYNOPSIS
+    http protocol
+.DESCRIPTION
+    Converts an http[s] protocol command to PowerShell.
+.EXAMPLE
+    .> {
+        https://api.github.com/repos/StartAutomating/PipeScript
+    }
+.EXAMPLE
+    {
+        get https://api.github.com/repos/StartAutomating/PipeScript
+    } | .>PipeScript
+.EXAMPLE
+    Invoke-PipeScript {
+        $GitHubApi = 'api.github.com'
+        $UserName  = 'StartAutomating'
+        https://$GitHubApi/users/$UserName
+    }
+.EXAMPLE
+    .> -ScriptBlock {
+        https://$GitHubApi/users/$UserName -GitHubApi api.github.com -UserName StartAutomating
+    }
+.EXAMPLE
+    .> -ScriptBlock {
+        https://$GitHubApi/users/$UserName -GitHubApi api.github.com -UserName StartAutomating
+    }
+.EXAMPLE
+    .> -ScriptBlock {
+        @(foreach ($repo in https://api.github.com/users/StartAutomating/repos?per_page=100) {
+            $repo | .Name .Stars { $_.stargazers_count }
+        }) | Sort-Object Stars -Descending
+    }
+.EXAMPLE
+.> {
+    http://text-processing.com/api/sentiment/ -Method POST -ContentType 'application/x-www-form-urlencoded' -Body "text=amazing!" |
+        Select-Object -ExpandProperty Probability -Property Label
+}
+#>
+[ValidateScript({
+    $commandAst = $_
+    if (-not ($commandAst.CommandElements[0..1].Value -match '^https{0,1}://')) {
+        return $false
+    }    
+    return $true
+})]
+param(
+# The URI.
+[Parameter(Mandatory,ValueFromPipeline)]
+[uri]
+$CommandUri,
+
+# The Command's Abstract Syntax Tree
+[Parameter(Mandatory)]
+[Management.Automation.Language.CommandAST]
+$CommandAst,
+
+[string]
+$Method = 'GET'
+)
+
+process {
+    $commandArguments  = @() + $CommandAst.ArgumentList
+    $commandParameters = [Ordered]@{} + $CommandAst.Parameter
+
+    $method      = ''
+    $commandName =         
+        if ($CommandAst.CommandElements[0].Value -match '://') {
+            $commandAst.CommandElements[0].Value
+        } else {
+            $method = $commandAst.CommandElements[0].Value
+            $commandArguments = $commandArguments[2..($commandArguments.Count + 1)]
+            $commandAst.CommandElements[1].Value
+        }        
+    
+    $startIndex = 0
+    $partsToJoin = 
+        @(
+            foreach ($match in [Regex]::Matches(
+                $commandName, '(?>
+                    (?<Variable>\$\w+\:\w+)
+                    |
+                    (?<Variable>\$\w+)
+                    )', 
+                    'IgnoreCase, IgnorePatternWhitespace'
+                )
+            ) {
+                "'" + 
+                    $commandName.Substring($startIndex, $match.Index - $startIndex).Replace("'", "''") + 
+                "'"
+                $varMatch = $match.Groups["Variable"].Value
+                $varName  = $varMatch.TrimStart('$')
+                if ($commandParameters[$varName]) {
+                    $varParameter = $commandParameters[$varName]
+                    $commandParameters.Remove($varName)
+                    if ($varParameter -is [string]) {
+                        "'" + $varParameter + "'"
+                    }
+                    elseif ($varParameter -is [ScriptBlock]) {
+                        "{$varParameter}"
+                    } else {
+                        $varParameter
+                    }
+                } else {
+                    $varMatch
+                }
+                
+                $startIndex = $match.Index + $match.Length        
+            }
+            "'" + 
+                $commandName.Substring($startIndex).Replace("'", "''") + 
+            "'"
+        )
+    
+    $invoker = "Invoke-RestMethod"
+    if ($commandParameters.Invoker) {
+        $invoker = "$($commandParameters.Invoker)"
+        $commandParameters.Remove('Invoker')
+    }
+    
+    if ($method) {
+        $commandParameters.Method = $method
+    }
+
+    
+    $newScript = 
+        if ($partsToJoin.Count -gt 1) {
+            "$Invoker ($($PartsToJoin -join ',') -join '') "
+        } else {
+            "$Invoker $PartsToJoin "
+        }
+    $newScript += @(
+        foreach ($argument in $commandArguments) {
+            if ($argument -is [string]) {
+                "'" + $argument.Replace("'", "''") + "'"
+            }
+            elseif ($argument -is [scriptblock]) {
+                "{" + $argument + "}"
+            }
+        }
+        foreach ($param in $commandParameters.GetEnumerator()) {
+            if ($param.Value -isnot [bool]) {
+                "-$($param.Key)"
+            }
+
+            if ($param.Value -is [string]) {
+                "'" + $param.Value.Replace("'", "''") + "'"
+            }
+            elseif ($param.Value -is [ScriptBlock]) {
+                "{" + $param.Value + "}"
+            }
+            elseif ($param.Value -is [bool]) {
+                if ($param.Value) {
+                    "-$($param.Key)"        
+                } else {
+                    "-$($param.Key):`$false"
+                }
+            }
+            else {
+                $param.Value
+            }
+        }
+    ) -join ' '
+    
+    [scriptblock]::Create($newScript)
+}

Transpilers/Protocols/Http.Protocol.tests.ps1

@@ -0,0 +1,16 @@
+describe 'http protocol' {
+    it 'Runs http[s] commands' {
+        .> https://api.github.com/repos/StartAutomating/PipeScript |
+            Select-Object -ExpandProperty Name |
+            Should -be PipeScript
+    }
+
+    it 'Can include variables in the syntax' {
+        .> {
+            $userName, $repo = 'StartAutomating', 'PipeScript'
+            https://api.github.com/repos/$userName/$repo |
+                Select-Object -ExpandProperty Name |
+                Should -be PipeScript
+        }
+    }
+}

Transpilers/Protocols/README.ps1.md

@@ -0,0 +1,34 @@
+PipeScript supports transpiling protocols.
+
+To be considered a protocol transpiler, a transpiler must:
+
+1. Accept a ```[uri]``` from the pipeline
+2. Have a parameter -CommandAST ```[Management.Automation.Language.CommandAST]``` 
+3. Be valid, given a ```[Management.Automation.Language.CommandAST]```
+
+~~~PipeScript{
+    [PSCustomObject]@{
+        Table = Get-Transpiler -TranspilerPath $pwd |
+            Select-Object DisplayName, Synopsis, @{
+                Name='Link'
+                Expression = { $_.Name }
+            }
+    }}
+~~~
+
+
+~~~PipeScript{
+    @(foreach ($transpiler in Get-Transpiler -TranspilerPath $pwd) {
+        $examples = @($transpiler.Examples)
+        if (-not $examples) { continue }
+        for ($exampleNumber = 1; $exampleNumber -le $examples.Length; $exampleNumber++) {
+            @("## $($transpiler.DisplayName) Example $($exampleNumber)", 
+                [Environment]::Newline,
+                "~~~PowerShell",                
+                $examples[$exampleNumber - 1],                
+                "~~~") -join [Environment]::Newline
+        }        
+    }) -join ([Environment]::Newline * 2)
+}
+~~~
+