Add Get-BloggerPost

.github/workflows/pester-tests.yml

@@ -20,6 +20,11 @@ jobs:
         Set-PSRepository PSGallery -InstallationPolicy Trusted
         Install-Module -Name Pester -Force -SkipPublisherCheck
         Install-Module -Name PowerShell-Yaml -Force -SkipPublisherCheck
+
+    - name: Install pandoc
+      shell: pwsh
+      run: |
+        choco install pandoc -y
 
     - name: Run Pester Tests
       shell: pwsh

README.md

@@ -52,6 +52,35 @@ A PowerShell library for publishing markdown files authored in markdown to Blogg
    Get-BloggerPosts
    ```
 
+1. Fetch an individual post from your blog
+
+   ```
+   Get-BloggerPost -PostId <postid>
+   ```
+
+   You can also persist the post to disk as HTML or markdown in the current directory. 
+
+   When using `HTML` format, files are saved as `<postid>.html`
+
+   When using `Markdown` format, files are saved as `<title>.md`
+
+   ```
+   Get-BloggerPost -PostId <postid> -Format HTML
+   Get-BloggerPost -PostId <postid> -Format Markdown
+   ```
+
+   You can specify an output directory where the file will be saved.
+
+   ```
+   Get-BloggerPost -PostId <postid> -OutDirectory "C:\MyPosts" -Format HTML
+   ```
+
+   You can also include a `FolderDateFormat` that uses the `published` property of the blog post to construct a subfolder.
+
+   ```
+   Get-BloggerPost -PostId <postId> -OutDirectory ".\Blog" -FolderDateFormat "YYYY\\MM" -Format Markdown
+   ```
+
 1. Publish a markdown file to your blog as draft
 
    ```

src/public/ConvertTo-HtmlFromMarkdown.ps1

@@ -1,6 +1,6 @@
 <#
 .SYNOPSIS
-    Convert a file to Markdown using Pandoc
+    Convert a Markdown file to HTML using Pandoc
 
 .PARAMETER File
     The file path of the markdown file

src/public/ConvertTo-MarkdownFromHtml.ps1

@@ -0,0 +1,73 @@
+<#
+.SYNOPSIS
+    Convert HTML content or a HTML file to Markdown using Pandoc
+
+.PARAMETER File
+    The file path of the html file. Required when Content is not specified.
+
+.PARAMETER Content
+    The HTML content to convert to Markdown. Required when File is not specified.
+
+.PARAMETER OutFile
+    The resulting markdown file, if specified.
+
+#>
+function ConvertTo-MarkdownFromHtml {
+  param(
+    [Parameter(Mandatory, ParameterSetName = "FromFile")]
+    [ValidateScript({ Test-Path $_ -PathType Leaf })]
+    [string]$File,
+
+    [Parameter(Mandatory, ParameterSetName = "FromContent")]
+    [string]$Content,
+
+    [Parameter(ParameterSetName = "FromFile")]
+    [Parameter(Mandatory=$false, ParameterSetName = "FromContent")]
+    [string]$OutFile
+  )
+
+  # when FromContent is specified, write the content to a temporary file
+  if ($PSCmdlet.ParameterSetName -eq "FromContent") {
+    # If content is provided, create a temporary file
+    $tempFile = [System.IO.Path]::GetTempFileName() + ".html"
+    Set-Content -Path $tempFile -Value $Content
+    $File = $tempFile
+  }
+
+  # ensure that the file is an absolute path because pandoc.exe doesn't like powershell relative paths
+  $File = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($File)
+
+  # Use pandoc to convert the markdown to Html 
+  $pandocArgs = "`"{0}`" " -f $File
+  $pandocArgs += "-f {0} " -f $BloggerSession.PandocHtmlFormat
+  $pandocArgs += "-t {0} " -f $BloggerSession.PandocMarkdownFormat
+
+  # add additional command-line arguments
+  if ($BloggerSession.PandocAdditionalArgs) {
+    Write-Verbose "Using additional args"
+    $pandocArgs += "{0} " -f $BloggerSession.PandocAdditionalArgs
+  }
+
+  if (!($OutFile)) {
+    $OutFile = Join-Path (Split-Path $File -Parent) ((Split-Path $File -LeafBase) + ".md")
+    Write-Verbose "Using OutFile: $OutFile"
+  }
+  # ensure that the file is an absolute path because pandoc.exe doesn't like powershell relative paths
+  $OutFile = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($OutFile)
+
+  $pandocArgs += "-o `"{0}`" " -f $OutFile
+
+  Write-Verbose ">> pandoc $($pandocArgs)"
+  Start-Process pandoc -ArgumentList $pandocArgs -NoNewWindow -Wait
+
+  $content = Get-Content $OutFile -Raw
+
+  # remove temporary files
+  if ($PSCmdlet.ParameterSetName -eq "FromContent") {
+    Remove-Item $File
+  } elseif (!$PSBoundParameters.ContainsKey("OutFile")) {
+    Remove-Item $OutFile
+  } 
+
+  return $content
+}

src/public/Get-BloggerPost.ps1

@@ -0,0 +1,145 @@
+<#
+.DESCRIPTION
+  Retrieves an individual post from a specified Blogger blog and optionally saves the content to a file as HTML or Markdown.
+
+.PARAMETER BlogId
+  The ID of the blog to retrieve the post from. If not specified, uses the BlogId in the user preferences.
+
+.PARAMETER PostId
+  The ID of the post to retrieve. This parameter is required.
+
+.PARAMETER Format
+  The format of the post content to retrieve. Use either Markdown or HTML.
+
+.PARAMETER FolderDateFormat
+  The folder name as expressed in a DateTime format string. For example, "YYYY/MM" which will save files
+  in a folder structure like "2023/10" based on the date of the post.
+
+.PARAMETER OutDirectory
+  The directory where the HTML file will be saved. If not specified, uses the current directory.
+
+.EXAMPLE
+  Get-BloggerPost -PostId "1234567890123456789"
+
+.EXAMPLE
+  Get-BloggerPost -BlogId "9876543210987654321" -PostId "1234567890123456789" -Format HTML -OutDirectory "C:\temp"
+
+.EXAMPLE
+  Get-BloggerPost -BlogId "9876543210987654321" -PostId "1234567890123456789" -Format Markdown -DateFormat "YYYY\\MM" -OutDirectory "C:\blogposts"
+#>
+Function Get-BloggerPost {
+  [CmdletBinding()]
+  param(
+    [Parameter(ParameterSetName = "Default")]
+    [Parameter(ParameterSetName = "Persist")]
+    [string]$BlogId,
+
+    [Parameter(Mandatory,ParameterSetName = "Default")]
+    [Parameter(Mandatory,ParameterSetName = "Persist")]
+    [string]$PostId,
+
+    [Parameter(Mandatory, ParameterSetName = "Persist")]
+    [ValidateSet("HTML", "Markdown")]
+    [string]$Format,
+
+    [Parameter(ParameterSetName ="Persist")]
+    [string]$FolderDateFormat,
+
+    [Parameter(ParameterSetName = "Persist")]
+    [string]$OutDirectory = (Get-Location).Path
+  )
+
+  if (!$PSBoundParameters.ContainsKey("BlogId")) {
+    $BlogId = $BloggerSession.BlogId
+    if ([string]::IsNullOrEmpty($BlogId) -or $BlogId -eq 0) {
+      throw "BlogId not specified and no default BlogId found in settings."
+    }
+  }
+
+  if ([string]::IsNullOrEmpty($PostId)) {
+    throw "PostId is required."
+  }
+
+  try {
+    $uri = "https://www.googleapis.com/blogger/v3/blogs/$BlogId/posts/$PostId"
+
+    $result = Invoke-GApi -uri $uri
+
+    if ($null -eq $result) {
+      throw "No post found with PostId '$PostId' in blog '$BlogId'."
+    }
+
+    # Construct a subfolder based on the published date
+    if ($FolderDateFormat -and $result.published) {
+      $date = [datetime]::Parse($result.published)
+      $formattedDate = $date.ToString($FolderDateFormat)
+      $OutDirectory = Join-Path -Path $OutDirectory -ChildPath $formattedDate
+    }
+
+    # Ensure the output directory exists
+    if (!(Test-Path -Path $OutDirectory)) {
+      try {
+        New-Item -ItemType Directory -Path $OutDirectory -Force | Out-Null
+      }
+      catch {
+        throw "Failed to create output directory '$OutDirectory': $($_.Exception.Message)"
+      }
+    }
+
+    # Extract the HTML content
+    $htmlContent = $result.content
+
+    if ([string]::IsNullOrEmpty($htmlContent)) {
+      Write-Warning "Post '$PostId' has no content."
+      $htmlContent = ""
+    }
+
+    # Create the output file path
+    try {
+
+      switch ($Format) {
+
+        # Save the HTML content to a file
+        "HTML" {
+
+          $fileName = "$PostId.html"
+          $filePath = Join-Path -Path $OutDirectory -ChildPath $fileName
+          $htmlContent | Out-File -FilePath $filePath -Encoding UTF8
+          Write-Verbose "Post content saved to: $filePath"
+        }
+
+        # Save the Post to a Markdown file
+        "Markdown" {
+
+          $title = $result.title
+          $frontMatter = [ordered]@{
+            postId = $result.id
+          }
+          $file = "$title.md"
+          $filePath = Join-Path -Path $OutDirectory -ChildPath $file
+          ConvertTo-MarkdownFromHtml -Content $result.content -OutFile $filePath > $null
+          Set-MarkdownFrontMatter -File $filePath -Replace $frontMatter
+          Write-Verbose "Post content saved to: $filePath"
+        }
+      }  
+
+      # Return the post object for further processing if needed
+      return $result
+    }
+    catch {
+      throw "Failed to save post content to file '$filePath': $($_.Exception.Message)"
+    }
+  }
+  catch {
+    # Handle specific HTTP errors
+    if ($_.Exception -like "*404*" -or $_.Exception -like "*Not Found*") {
+      throw "Post with PostId '$PostId' not found in blog '$BlogId'. Please verify the PostId and BlogId are correct."
+    }
+    elseif ($_.Exception -like "*403*" -or $_.Exception -like "*Forbidden*") {
+      throw "Access denied to blog '$BlogId' or post '$PostId'. Please verify your permissions."
+    }
+    else {
+      Write-Error $_.ToString() -ErrorAction Stop
+    }
+  }
+}

src/tests/ConvertTo-MarkdownFromHtml.Tests.ps1

@@ -0,0 +1,79 @@
+Describe "ConvertTo-MarkdownFromHtml" {
+  BeforeAll {
+    Import-Module $PSScriptRoot\_TestHelpers.ps1 -Force
+
+  }
+
+  BeforeEach {
+    Import-Module $PSScriptRoot\..\PSBlogger.psm1 -Force
+  }
+
+  Context "Using Content" {
+
+    BeforeEach {
+      $outFile = "TestDrive:\123.md"
+      $htmlContent = "<h1>Hello World</h1>"
+    }
+
+    AfterEach {
+      if (Test-Path $outFile) {
+        Remove-Item $outFile -Force
+      }
+    }
+
+    It "Should save HTML content to a markdown file" {
+      # act
+      ConvertTo-MarkdownFromHtml -Content $htmlContent -OutFile $outFile
+
+      # assert
+      Test-Path $outFile | Should -BeTrue
+    }
+
+    It "Should convert HTML content to Markdown file" {
+      # act
+      $content = ConvertTo-MarkdownFromHtml -Content $htmlContent -OutFile $outFile
+
+      # assert
+      $content = (Get-Content -Path $outFile -Raw).Split("`r")
+      $content[0] | Should -Be "# Hello World"
+    }
+
+    It "Should not persist to disk if OutFile is not specified" {
+      # act
+      $content = ConvertTo-MarkdownFromHtml -Content $htmlContent
+
+      # assert
+      $content | Should -Not -BeNullOrEmpty
+      Test-Path $outFile | Should -BeFalse
+    }
+  }
+
+  Context "Using File" {
+
+    BeforeEach {
+      $htmlContent = "<h1>Hello World</h1>"
+      $htmlFile = "TestDrive:\123.html"
+      $markdownFile = "TestDrive:\123.md"
+      Set-Content -Path $htmlFile -Value $htmlContent
+    }
+
+    It "Should convert HTML file to Markdown" {
+      # act
+      $content = ConvertTo-MarkdownFromHtml -File $htmlFile -OutFile $markdownFile
+
+      # assert
+      Test-Path $markdownFile | Should -BeTrue
+      $content = (Get-Content -Path $markdownFile -Raw).Split("`r")
+      $content[0] | Should -Be "# Hello World"
+    }
+
+    It "Should delete temporary file" {
+      # act
+      $content = ConvertTo-MarkdownFromHtml -File $htmlFile
+
+      # assert
+      $content | Should -Not -BeNullOrEmpty
+      Test-Path $markdownFile | Should -BeFalse
+    }
+  }
+}