javascript - How to use webkitRequestFileSystem at file: protocol -

according exploring filesystem apis at

browser support & storage limitations

you may need --allow-file-access-from-files flag if you're debugging app file://. not using these flags result in security_err or quota_exceeded_err fileerror.

launched chromium --allow-file-access-from-files , --unlimited-storage , possibly deprecated --unlimited-quota-for-files; --unsafely-treat-insecure-origin-as-secure=file:///path/to/directory/* --user-data-dir=/path/to/directory set.

interestingly, when chromium opens notification displayed

you using unsupported command-line flag: --unsafely-treat-insecure-origin-as-secure. stability , security suffer.

there other flags not specified can used; ignored notification still able set , localstorage @ file: protocol, spcecifically files @ file:///path/to/directory/*, though

navigator.webkittemporarystorage.requestquota(1024*1024, function(grantedbytes) {   console.log(grantedbytes) }, errorhandler); 

logged 0, errorhandler is

function errorhandler(e) {   console.log(e) } 

also

function writefile(fs) {   fs.root.getfile("file.txt", {create: true}, function(fileentry) {     fileentry.createwriter(function(filewriter) {       filewriter.onwriteend = function(e) {         // call `readfile`         window.requestfilesystem(window.temporary, 1024*1024, readfile, errorhandler);       };       filewriter.onerror = errorhandler;       var blob = new blob(["abc"], {type: "text/plain"});       filewriter.write(blob);     }, errorhandler);   }, errorhandler); }  window.requestfilesystem(window.temporary, 1024*1024, writefile, errorhandler);  function readfile(fs) {   fs.root.getfile("file.txt", {}, function(fileentry) {     fileentry.file(function(file) {        var reader = new filereader();        reader.onloadend = function(e) {          console.log(e.target.result)        };        reader.readastext(file);     }, errorhandler);   }, errorhandler); } 

logged

fileerror {code: 7, name: "invalidstateerror", message: "an operation depends on state cached in in…he state had changed since read disk."} code:7 message:"an operation depends on state cached in interface object made state had changed since read disk." name:"invalidstateerror" __proto__:domerror 

question: modifications necessary @ launch flags, workarounds or other approaches allow use of webkitrequestfilesystem @ file: protocol?

the initial try received errors @ terminal relating lack of space on device. received 2 separate errors code 7 invalidstateerror , code 3 aborterror. note, chromium launched in sandbox @ each configuration.

was able achieve expected result of writing filesystem @ file: protocol adjusting launch flags --allow-file-access-from-files , specifying different chromium configuration folder @ --user-data-dir=/newer/version/of/profile/folder; --unlimited-quota-for-files , --unsafely-treat-insecure-origin-as-secure=file:///path/to/directory/* not necessary achieve requirement.

not entirely why original profile folder using logged errors when attempting access filesystem @ file: protocol. folder have been previous version of chromium. launch new or newest version chromium command-line chromium folder in configuration directory may have been older version preferences set. when reviewed terminal @ 1 point no space left on disk message logged in relation filesystem when launched using former profile configuration folder. tried newer version of chromium profile folder solved issue.

much credit solution due @patrickevans verifying process indeed possible; more user error limiting realization of expected result.

var requestedbytes = 16,   _grantedbytes;  function errorhandler(e) {   console.log(e) }  function writefile(fs) {   console.log(fs)   fs.root.getfile("file.txt", {     create: true   }, function(fileentry) {     fileentry.createwriter(function(filewriter) {       filewriter.onwriteend = function(e) {         // call `readfile`         console.log(_grantedbytes);         window.webkitrequestfilesystem(window.temporary                                       , _grantedbytes                                       , readfile                                       , errorhandler);       };       filewriter.onerror = errorhandler;       var blob = new blob(["abc"], {         type: "text/plain"       });       filewriter.write(blob);     }, errorhandler);   }, errorhandler); }  navigator.webkittemporarystorage.requestquota(requestedbytes , function(grantedbytes) {     console.log(grantedbytes);     _grantedbytes = grantedbytes;     window.webkitrequestfilesystem(window.temporary                                   , grantedbytes                                   , writefile                                   , errorhandler);  }, errorhandler);  function readfile(fs) {   fs.root.getfile("file.txt", {}, function(fileentry) {     fileentry.file(function(file) {       var reader = new filereader();       reader.onloadend = function(e) {         console.log(e.target.result, fileentry.tourl());       };       reader.readastext(file);     }, errorhandler);   }, errorhandler); }