Lianja Requires Chilkat v11.0.0+
Lianja
Google Drive - Build a Local Cache of Metadata
See more Google Drive Examples
This example demonstrates how to download the metadata for all files in a Google Drive account to create a local filesystem cache with the information. The cache can be used to fetch information without having to query Google Drive.Chilkat Lianja Downloads
llSuccess = .F.
llSuccess = .T.
// It requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
// This example uses a previously obtained access token having permission for the
// Google Drive scope.
loGAuth = createobject("CkAuthGoogle")
loGAuth.AccessToken = "GOOGLE_DRIVE_ACCESS_TOKEN"
loRest = createobject("CkRest")
// Connect using TLS.
llBAutoReconnect = .T.
llSuccess = loRest.Connect("www.googleapis.com",443,.T.,llBAutoReconnect)
// Provide the authentication credentials (i.e. the access token)
loRest.SetAuthGoogle(loGAuth)
// -------------------------------------------------------------------
// Initialize our cache object. Indicate the location of the root cache directory, and how many cache levels are to exist.
// For small caches (level 0) all cache files are in the root directory.
// For medium caches (level 1) cache files are located in 256 sub-directories from the root.
// For large caches (level 2) cache files are located in 256x256 sub-directories two levels down from the root.
loGdCache = createobject("CkCache")
loGdCache.Level = 0
// Use a root directory that makes sense on your operating system..
loGdCache.AddRoot("C:/ckCache/googleDrive")
// If we are re-building the cache, we can first delete the entire contents of the cache.
lnNumCacheFilesDeleted = loGdCache.DeleteAll()
// Create a date/time object with an time 7 days from the current date/time.
loDtExpire = createobject("CkDateTime")
loDtExpire.SetFromCurrentSystemTime()
loDtExpire.AddDays(7)
// Indicate that we want ALL possible fields.
// If no fields are indicated, then only the basic fields are returned.
lcAllFields = "appProperties,capabilities,contentHints,createdTime,description,explicitlyTrashed,fileExtension,folderColorRgb,fullFileExtension,headRevisionId,iconLink,id,imageMediaMetadata,isAppAuthorized,kind,lastModifyingUser,md5Checksum,mimeType,modifiedByMeTime,modifiedTime,name,originalFilename,ownedByMe,owners,parents,permissions,properties,quotaBytesUsed,shared,sharedWithMeTime,sharingUser,size,spaces,starred,thumbnailLink,trashed,version,videoMediaMetadata,viewedByMe,viewedByMeTime,viewersCanCopyContent,webContentLink,webViewLink,writersCanShare"
// We're going to keep a master list of fileId's as we iterate over all the files in this Google Drive account.
// This master list will also be saved to the cache under the key "AllGoogleDriveFileIds".
loJsonMaster = createobject("CkJsonObject")
loJsonMasterArr = createobject("CkJsonArray")
loJsonMaster.AppendArray2("fileIds",loJsonMasterArr)
// Also keep a list of file paths.
loJsonMasterPaths = createobject("CkJsonArray")
loJsonMaster.AppendArray2("filePaths",loJsonMasterPaths)
// The default page size is 100, with a max of 1000.
loRest.AddQueryParam("pageSize","200")
loJson = createobject("CkJsonObject")
// Send the request for the 1st page.
lcJsonResponse = loRest.FullRequestNoBody("GET","/drive/v3/files")
lnPageNumber = 1
llBContinueLoop = loRest.LastMethodSuccess and (loRest.ResponseStatusCode = 200)
do while llBContinueLoop = .T.
? "---- Page " + str(lnPageNumber) + " ----"
loJson.Load(lcJsonResponse)
lnNumFiles = loJson.SizeOfArray("files")
i = 0
do while i < lnNumFiles
// Add this file ID to the master list.
loJson.I = i
loJsonMasterArr.AddStringAt(-1,loJson.StringOf("files[i].id"))
i = i + 1
enddo
// Get the next page of files.
// If the "nextPageToken" is present in the JSON response, then use it in the "pageToken" parameter
// for the next request. If no "nextPageToken" was present, then this was the last page of files.
lcPageToken = loJson.StringOf("nextPageToken")
llBContinueLoop = .F.
llBHasMorePages = loJson.LastMethodSuccess
if (llBHasMorePages = .T.) then
loRest.ClearAllQueryParams()
loRest.AddQueryParam("pageSize","200")
loRest.AddQueryParam("pageToken",lcPageToken)
lcJsonResponse = loRest.FullRequestNoBody("GET","/drive/v3/files")
llBContinueLoop = loRest.LastMethodSuccess and (loRest.ResponseStatusCode = 200)
lnPageNumber = lnPageNumber + 1
endif
enddo
// Check to see if the above loop exited with errors...
if (loRest.LastMethodSuccess = .F.) then
? loRest.LastErrorText
release loGAuth
release loRest
release loGdCache
release loDtExpire
release loJsonMaster
release loJsonMasterArr
release loJsonMasterPaths
release loJson
return
endif
// Check to see if the above loop exited with errors...
// A successful response will have a status code equal to 200.
if (loRest.ResponseStatusCode <> 200) then
? "response status code = " + str(loRest.ResponseStatusCode)
? "response status text = " + loRest.ResponseStatusText
? "response header: " + loRest.ResponseHeader
? "response JSON: " + lcJsonResponse
release loGAuth
release loRest
release loGdCache
release loDtExpire
release loJsonMaster
release loJsonMasterArr
release loJsonMasterPaths
release loJson
return
endif
// Iterate over the file IDs and download the metadata for each, saving each to the cache...
// Also, keep in-memory hash entries of the name and parent[0] so we can quickly
// build the path-->fileId cache entries. (Given that the Google Drive REST API uses
// fileIds, this gives us an easy way to lookup a fileId based on a filePath.)
loHashTable = createobject("CkHashtable")
// Set the capacity of the hash table to something reasonable for the number of files
// to be hashed.
loHashTable.ClearWithNewCapacity(521)
loSbPathForFileId = createobject("CkStringBuilder")
// Used for storing the file name and parents[0] in the hashTable.
loSaFileInfo = createobject("CkStringArray")
loSaFileInfo.Unique = .F.
lnNumFiles = loJsonMaster.SizeOfArray("fileIds")
i = 0
do while i < lnNumFiles
loJsonMaster.I = i
lcFileId = loJsonMaster.StringOf("fileIds[i]")
loSbPathForFileId.SetString("/drive/v3/files/")
loSbPathForFileId.Append(lcFileId)
loRest.ClearAllQueryParams()
loRest.AddQueryParam("fields",lcAllFields)
lcJsonResponse = loRest.FullRequestNoBody("GET",loSbPathForFileId.GetAsString())
if ((loRest.LastMethodSuccess <> .T.) or (loRest.ResponseStatusCode <> 200)) then
// Force an exit of this loop..
lnNumFiles = 0
endif
// Save this file's metadata to the local cache.
// The lookup key is the fileId.
loGdCache.SaveTextDt(lcFileId,loDtExpire,"",lcJsonResponse)
// Get this file's name and parent[0], and put this information
// in our in-memory hashtable to be used below..
loJson.Load(lcJsonResponse)
loSaFileInfo.Clear()
loSaFileInfo.Append(loJson.StringOf("name"))
loSaFileInfo.Append(loJson.StringOf("parents[0]"))
loHashTable.AddStr(lcFileId,loSaFileInfo.Serialize())
? loJson.StringOf("name") + ", " + loJson.StringOf("parents[0]")
i = i + 1
enddo
// Check to see if the above loop exited with errors...
if (loRest.LastMethodSuccess = .F.) then
? loRest.LastErrorText
release loGAuth
release loRest
release loGdCache
release loDtExpire
release loJsonMaster
release loJsonMasterArr
release loJsonMasterPaths
release loJson
release loHashTable
release loSbPathForFileId
release loSaFileInfo
return
endif
// Check to see if the above loop exited with errors...
// A successful response will have a status code equal to 200.
if (loRest.ResponseStatusCode <> 200) then
? "response status code = " + str(loRest.ResponseStatusCode)
? "response status text = " + loRest.ResponseStatusText
? "response header: " + loRest.ResponseHeader
? "response JSON: " + lcJsonResponse
release loGAuth
release loRest
release loGdCache
release loDtExpire
release loJsonMaster
release loJsonMasterArr
release loJsonMasterPaths
release loJson
release loHashTable
release loSbPathForFileId
release loSaFileInfo
return
endif
// Now that all the fileId's are in the cache, let's build the directory path
// for each fileID.
// (Technically, a fileId can have multiple parents, which means it can be in multiple directories
// at once. This is only going to build directory paths following the 0'th parent ID in the parents list.)
// The directory path for files in "My Drive" will be just the filename.
// For files in sub-directories, the path will be relative, such as "subdir1/subdir2/something.pdf"
//
? "---- building paths ----"
loSbPath = createobject("CkStringBuilder")
lnNumFiles = loJsonMaster.SizeOfArray("fileIds")
i = 0
do while i < lnNumFiles
loJsonMaster.I = i
loSbPath.Clear()
lcFileId = loJsonMaster.StringOf("fileIds[i]")
llBFinished = .F.
do while (llBFinished = .F.)
loSaFileInfo.Clear()
loSaFileInfo.AppendSerialized(loHashTable.LookupStr(lcFileId))
// Append this file or directory name.
loSbPath.Prepend(loSaFileInfo.GetString(0))
// Get the parent fileId
lcFileId = loSaFileInfo.GetString(1)
// If this fileId is not in the hashtable, then it's the fileId for "My Drive", and we are finished.
if (loHashTable.Contains(lcFileId) = .F.) then
llBFinished = .T.
else
loSbPath.Prepend("/")
endif
enddo
? str(i) + ": " + loSbPath.GetAsString()
// Store the filePath --> fileId mapping in our local cache.
lcFileId = loJsonMaster.StringOf("fileIds[i]")
loGdCache.SaveTextDt(loSbPath.GetAsString(),loDtExpire,"",lcFileId)
loJsonMasterPaths.AddStringAt(-1,loSbPath.GetAsString())
i = i + 1
enddo
// Save the master list of file IDs and file paths to the local cache.
loJsonMaster.EmitCompact = .F.
lcStrJsonMaster = loJsonMaster.Emit()
loGdCache.SaveTextNoExpire("AllGoogleDriveFileIds","",lcStrJsonMaster)
? "JSON Master Record:"
? lcStrJsonMaster
// The JSON Master Cache Record looks something like this:
// An application can load the JSON master record and iterate over all the files
// in Google Drive by file ID, or by path.
// {
// "fileIds": [
// "0B53Q6OSTWYolQlExSlBQT1phZXM",
// "0B53Q6OSTWYolVHRPVkxtYWFtZkk",
// "0B53Q6OSTWYolRGZEV3ZGUTZfNFk",
// "0B53Q6OSTWYolS2FXSjliMXQxSU0",
// "0B53Q6OSTWYolZUhxckMzb0dRMzg",
// "0B53Q6OSTWYolbUF6WS1Gei1oalk",
// "0B53Q6OSTWYola296ODZUSm5GYU0",
// "0B53Q6OSTWYolbTE3c3J5RHBUcHM",
// "0B53Q6OSTWYolTmhybWJSUGd5Q2c",
// "0B53Q6OSTWYolY2tPU1BnYW02T2c",
// "0B53Q6OSTWYolTTBBR2NvUE81Zzg",
// ],
// "filePaths": [
// "testFolder/abc/123/pigs.json",
// "testFolder/starfish20.jpg",
// "testFolder/penguins2.jpg",
// "testFolder/starfish.jpg",
// "testFolder/abc/123/starfish.jpg",
// "testFolder/abc/123/penguins.jpg",
// "testFolder/abc/123",
// "testFolder/abc",
// "testFolder/testHello.txt",
// "testFolder",
// "helloWorld.txt",
// ]
// }
? "Entire cache rebuilt..."
release loGAuth
release loRest
release loGdCache
release loDtExpire
release loJsonMaster
release loJsonMasterArr
release loJsonMasterPaths
release loJson
release loHashTable
release loSbPathForFileId
release loSaFileInfo
release loSbPath