BsonFile

0.0.1

Scripts/Save-BsonFile.ps1

<#
.Synopsis
    Saves the special file based collection to its source file.
 
.Description
    The command exports the collection created by Open-BsonFile to its file.
 
.Parameter Collection
        Specifies the collection instance. If it is defined by the variable
        $Collection then the parameter may be omitted.
 
.Parameter Path
        Specifies the source file to be saved. Its collection does not have to
        be opened, it is discovered by the file path. But the collection must
        exist.
 
.Parameter Force
        Tells to save even if the source file was removed or modified
        externally. By default, the command fails in such cases.
 
.Parameter Result
        Tells to output some file collection information.
 
.Parameter Changed
        Tells to save only if the collection is changed since the last sync.
        This option is effective with replica sets and shards.
 
.Outputs
    None or the information document.
 
.Link
    Open-BsonFile
#>

function Save-BsonFile {
    [CmdletBinding(DefaultParameterSetName='Collection')]
    param(
        [Parameter(ParameterSetName='Collection', Position=0)]
        [MongoDB.Driver.IMongoCollection[MongoDB.Bson.BsonDocument]]$Collection,
        [Parameter(ParameterSetName='Path', Position=0, Mandatory=1)]
        [string]$Path,
        [switch]$Force,
        [switch]$Result,
        [switch]$Changed
    )

    trap {Write-Error -ErrorRecord $_}

    Connect-Mdbc . BsonFile

    # resolve $Path, $md5, $info, $Collection
    if ($Path) {
        $Path = $PSCmdlet.GetUnresolvedProviderPathFromPSPath($Path)
        $md5 = Get-BFPathMD5 $Path
        $info = Get-BFIndexInfo $md5
        if (!$info) {
            throw "File has no connected collection: '$Path'."
        }
        $Collection = Get-MdbcCollection $md5
    }
    else {
        . Resolve-BFCollection
    }

    # check file times and changes
    if (!$Force) {
        # file times
        $item = Get-Item -LiteralPath $Path
        if (!(Test-BFSameFileTime $info $item)) {
            throw "Different file times: expected $($info.FileTime.ToLocalTime()), actual $($item.LastWriteTime)."
        }

        # changes
        if ($Changed -and $info.SyncStamp) {
            $op = New-Object MongoDB.Driver.ChangeStreamOptions
            $op.StartAtOperationTime = $info.SyncStamp
            $op.BatchSize = 1
            $changes = $(
                $watch = Watch-MdbcChange -Collection $Collection -Options $op
                try {
                    if ($watch.MoveNext()) {$watch.Current}
                    if ($watch.MoveNext()) {$watch.Current}
                }
                finally {
                    $watch.Dispose()
                }
            )
            if (!$changes) {
                if ($Result) {
                    $info.IsExported = $false
                    $info
                }
                return
            }
        }
    }

    # export
    Get-MdbcData | Export-MdbcData $Path

    # set index
    $item = Get-Item -LiteralPath $Path
    $info.FileTime = $item.LastWriteTimeUtc
    $info.SyncTime = $item.LastWriteTimeUtc
    $info.SyncStamp = Get-BFNextTimestamp
    Set-BFIndexInfo $info

    # result
    if ($Result) {
        if ($Changed) {
            $info.IsExported = $true
        }
        $info
    }
}