[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[],[],null,["# Google Auth Library Client - Class FileSource (1.47.1)\n\nVersion latestkeyboard_arrow_down\n\n- [1.47.1 (latest)](/php/docs/reference/auth/latest/CredentialSource.FileSource)\n- [1.47.0](/php/docs/reference/auth/1.47.0/CredentialSource.FileSource)\n- [1.46.0](/php/docs/reference/auth/1.46.0/CredentialSource.FileSource)\n- [1.45.2](/php/docs/reference/auth/1.45.2/CredentialSource.FileSource) \nReference documentation and code samples for the Google Auth Library Client class FileSource.\n\nRetrieve a token from a file.\n\nNamespace\n---------\n\nGoogle \\\\ Auth \\\\ CredentialSource\n\nMethods\n-------\n\n### __construct\n\n### fetchSubjectToken\n\n### getCacheKey\n\nGets the unique key for caching.\n\nThe format for the cache key one of the following:\nFilename"]]