Swift
Swift
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 Swift Downloads
func chilkatTest() {
var success: Bool = false
success = true
// 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.
let gAuth = CkoAuthGoogle()!
gAuth.accessToken = "GOOGLE_DRIVE_ACCESS_TOKEN"
let rest = CkoRest()!
// Connect using TLS.
var bAutoReconnect: Bool = true
success = rest.connect(hostname: "www.googleapis.com", port: 443, tls: true, autoReconnect: bAutoReconnect)
// Provide the authentication credentials (i.e. the access token)
rest.setAuthGoogle(authProvider: gAuth)
// -------------------------------------------------------------------
// 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.
let gdCache = CkoCache()!
gdCache.level = 0
// Use a root directory that makes sense on your operating system..
gdCache.addRoot(path: "C:/ckCache/googleDrive")
// If we are re-building the cache, we can first delete the entire contents of the cache.
var numCacheFilesDeleted: Int = gdCache.deleteAll().intValue
// Create a date/time object with an time 7 days from the current date/time.
let dtExpire = CkoDateTime()!
dtExpire.setFromCurrentSystemTime()
dtExpire.addDays(numDays: 7)
// Indicate that we want ALL possible fields.
// If no fields are indicated, then only the basic fields are returned.
var allFields: String? = "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".
let jsonMaster = CkoJsonObject()!
let jsonMasterArr = CkoJsonArray()!
jsonMaster.appendArray2(name: "fileIds", jarr: jsonMasterArr)
// Also keep a list of file paths.
let jsonMasterPaths = CkoJsonArray()!
jsonMaster.appendArray2(name: "filePaths", jarr: jsonMasterPaths)
// The default page size is 100, with a max of 1000.
rest.addQueryParam(name: "pageSize", value: "200")
let json = CkoJsonObject()!
var jsonFileMetadata: CkoJsonObject?
var i: Int
var numFiles: Int
// Send the request for the 1st page.
var jsonResponse: String? = rest.fullRequestNoBody(httpVerb: "GET", uriPath: "/drive/v3/files")
var pageNumber: Int = 1
var pageToken: String?
var bContinueLoop: Bool = rest.lastMethodSuccess && (rest.responseStatusCode.intValue == 200)
while bContinueLoop == true {
print("---- Page \(pageNumber) ----")
json.load(json: jsonResponse)
numFiles = json.size(ofArray: "files").intValue
i = 0
while i < numFiles {
// Add this file ID to the master list.
json.i = i
jsonMasterArr.addString(at: -1, value: json.string(of: "files[i].id"))
i = i + 1
}
// 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.
pageToken = json.string(of: "nextPageToken")
bContinueLoop = false
var bHasMorePages: Bool = json.lastMethodSuccess
if bHasMorePages == true {
rest.clearAllQueryParams()
rest.addQueryParam(name: "pageSize", value: "200")
rest.addQueryParam(name: "pageToken", value: pageToken)
jsonResponse = rest.fullRequestNoBody(httpVerb: "GET", uriPath: "/drive/v3/files")
bContinueLoop = rest.lastMethodSuccess && (rest.responseStatusCode.intValue == 200)
pageNumber = pageNumber + 1
}
}
// Check to see if the above loop exited with errors...
if rest.lastMethodSuccess == false {
print("\(rest.lastErrorText!)")
return
}
// Check to see if the above loop exited with errors...
// A successful response will have a status code equal to 200.
if rest.responseStatusCode.intValue != 200 {
print("response status code = \(rest.responseStatusCode.intValue)")
print("response status text = \(rest.responseStatusText!)")
print("response header: \(rest.responseHeader!)")
print("response JSON: \(jsonResponse!)")
return
}
// 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.)
let hashTable = CkoHashtable()!
// Set the capacity of the hash table to something reasonable for the number of files
// to be hashed.
hashTable.clear(withNewCapacity: 521)
let sbPathForFileId = CkoStringBuilder()!
// Used for storing the file name and parents[0] in the hashTable.
let saFileInfo = CkoStringArray()!
saFileInfo.unique = false
var fileId: String?
numFiles = jsonMaster.size(ofArray: "fileIds").intValue
i = 0
while i < numFiles {
jsonMaster.i = i
fileId = jsonMaster.string(of: "fileIds[i]")
sbPathForFileId.setString(value: "/drive/v3/files/")
sbPathForFileId.append(value: fileId)
rest.clearAllQueryParams()
rest.addQueryParam(name: "fields", value: allFields)
jsonResponse = rest.fullRequestNoBody(httpVerb: "GET", uriPath: sbPathForFileId.getAsString())
if (rest.lastMethodSuccess != true) || (rest.responseStatusCode.intValue != 200) {
// Force an exit of this loop..
numFiles = 0
}
// Save this file's metadata to the local cache.
// The lookup key is the fileId.
gdCache.saveTextDt(key: fileId, expire: dtExpire, eTag: "", strData: jsonResponse)
// Get this file's name and parent[0], and put this information
// in our in-memory hashtable to be used below..
json.load(json: jsonResponse)
saFileInfo.clear()
saFileInfo.append(str: json.string(of: "name"))
saFileInfo.append(str: json.string(of: "parents[0]"))
hashTable.addStr(key: fileId, value: saFileInfo.serialize())
print("\(json.string(of: "name")!), \(json.string(of: "parents[0]")!)")
i = i + 1
}
// Check to see if the above loop exited with errors...
if rest.lastMethodSuccess == false {
print("\(rest.lastErrorText!)")
return
}
// Check to see if the above loop exited with errors...
// A successful response will have a status code equal to 200.
if rest.responseStatusCode.intValue != 200 {
print("response status code = \(rest.responseStatusCode.intValue)")
print("response status text = \(rest.responseStatusText!)")
print("response header: \(rest.responseHeader!)")
print("response JSON: \(jsonResponse!)")
return
}
// 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"
//
print("---- building paths ----")
let sbPath = CkoStringBuilder()!
numFiles = jsonMaster.size(ofArray: "fileIds").intValue
i = 0
while i < numFiles {
jsonMaster.i = i
sbPath.clear()
fileId = jsonMaster.string(of: "fileIds[i]")
var bFinished: Bool = false
while (bFinished == false) {
saFileInfo.clear()
saFileInfo.appendSerialized(encodedStr: hashTable.lookupStr(key: fileId))
// Append this file or directory name.
sbPath.prepend(value: saFileInfo.getString(index: 0))
// Get the parent fileId
fileId = saFileInfo.getString(index: 1)
// If this fileId is not in the hashtable, then it's the fileId for "My Drive", and we are finished.
if hashTable.contains(key: fileId) == false {
bFinished = true
}
else {
sbPath.prepend(value: "/")
}
}
print("\(i): \(sbPath.getAsString()!)")
// Store the filePath --> fileId mapping in our local cache.
fileId = jsonMaster.string(of: "fileIds[i]")
gdCache.saveTextDt(key: sbPath.getAsString(), expire: dtExpire, eTag: "", strData: fileId)
jsonMasterPaths.addString(at: -1, value: sbPath.getAsString())
i = i + 1
}
// Save the master list of file IDs and file paths to the local cache.
jsonMaster.emitCompact = false
var strJsonMaster: String? = jsonMaster.emit()
gdCache.saveTextNoExpire(key: "AllGoogleDriveFileIds", eTag: "", strData: strJsonMaster)
print("JSON Master Record:")
print("\(strJsonMaster!)")
// 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",
// ]
// }
print("Entire cache rebuilt...")
}