global_persistence/lib/media_handler.js

A link between LRU and messaging to peers which may store or cache LRU entries remotely

const Repository = require('repository-bridge')

const fs = require('fs')
//
const DEFAULT_P2P_REPO = 'local'



let g_media_types = {
    "audio" : { "encrypted" : true, "store_local" : true, "store_repo" : true },
    "video" : { "encrypted" : false, "store_local" : true, "store_repo" : true },
    "image" : { "encrypted" : true, "store_local" : true, "store_repo" : true },
    "text" : { "encrypted" : true, "store_local" : true, "store_repo" : false }
}


let types_to_general_media_types = {
  "3dm": "x-world",
  "x-3dmf": "x-world",
  "3dmf": "x-world",
  "a": "application",
  "octet-stream": "application",
  "aab": "application",
  "x-authorware-bin": "application",
  "aam": "application",
  "x-authorware-map": "application",
  "aas": "application",
  "x-authorware-seg": "application",
  "abc": "text",
  "vnd.abc": "text",
  "acgi": "text",
  "html": "text",
  "afl": "video",
  "animaflex": "video",
  "ai": "application",
  "postscript": "application",
  "aif": "audio",
  "aiff": "audio",
  "x-aiff": "audio",
  "aifc": "audio",
  "aim": "application",
  "x-aim": "application",
  "aip": "text",
  "x-audiosoft-intra": "text",
  "ani": "application",
  "x-navi-animation": "application",
  "aos": "application",
  "x-nokia-9000-communicator-add-on-software": "application",
  "aps": "application",
  "mime": "www",
  "arc": "application",
  "arj": "application",
  "art": "image",
  "x-jg": "image",
  "asf": "video",
  "x-ms-asf": "video",
  "asm": "text",
  "x-asm": "text",
  "asp": "text",
  "asx": "video",
  "x-mplayer2": "application",
  "x-ms-asf-plugin": "video",
  "au": "audio",
  "basic": "audio",
  "x-au": "audio",
  "avi": "video",
  "x-troff-msvideo": "application",
  "msvideo": "video",
  "x-msvideo": "video",
  "avs": "video",
  "avs-video": "video",
  "bcpio": "application",
  "x-bcpio": "application",
  "bin": "application",
  "mac-binary": "application",
  "macbinary": "application",
  "x-binary": "application",
  "x-macbinary": "application",
  "bm": "image",
  "bmp": "image",
  "x-windows-bmp": "image",
  "boo": "application",
  "book": "application",
  "boz": "application",
  "x-bzip2": "application",
  "bsh": "application",
  "x-bsh": "application",
  "bz": "application",
  "x-bzip": "application",
  "bz2": "application",
  "c": "text",
  "plain": "text",
  "x-c": "text",
  "c++": "text",
  "cat": "application",
  "vnd.ms-pki.seccat": "application",
  "cc": "text",
  "ccad": "application",
  "clariscad": "application",
  "cco": "application",
  "x-cocoa": "application",
  "cdf": "application",
  "x-cdf": "application",
  "x-netcdf": "application",
  "cer": "application",
  "pkix-cert": "application",
  "x-x509-ca-cert": "application",
  "cha": "application",
  "x-chat": "application",
  "chat": "application",
  "class": "application",
  "java": "text",
  "java-byte-code": "application",
  "x-java-class": "application",
  "com": "text",
  "conf": "text",
  "cpio": "application",
  "x-cpio": "application",
  "cpp": "text",
  "cpt": "application",
  "mac-compactpro": "application",
  "x-compactpro": "application",
  "x-cpt": "application",
  "crl": "application",
  "pkcs-crl": "application",
  "pkix-crl": "application",
  "crt": "application",
  "x-x509-user-cert": "application",
  "csh": "text",
  "x-csh": "application",
  "x-script.csh": "text",
  "css": "text",
  "x-pointplus": "application",
  "cxx": "text",
  "dcr": "application",
  "x-director": "application",
  "deepv": "application",
  "x-deepv": "application",
  "def": "text",
  "der": "application",
  "dif": "video",
  "x-dv": "video",
  "dir": "application",
  "dl": "video",
  "x-dl": "video",
  "doc": "application",
  "msword": "application",
  "dot": "application",
  "dp": "application",
  "commonground": "application",
  "drw": "application",
  "drafting": "application",
  "dump": "application",
  "dv": "video",
  "dvi": "application",
  "x-dvi": "application",
  "dwf": "model",
  "(old)": "drawing",
  "vnd.dwf": "model",
  "dwg": "image",
  "acad": "application",
  "vnd.dwg": "image",
  "x-dwg": "image",
  "dxf": "image",
  "dxr": "application",
  "el": "text",
  "x-script.elisp": "text",
  "elc": "application",
  "(compiled": "application",
  "x-elc": "application",
  "env": "application",
  "x-envoy": "application",
  "eps": "application",
  "es": "application",
  "x-esrehber": "application",
  "etx": "text",
  "x-setext": "text",
  "evy": "application",
  "envoy": "application",
  "exe": "application",
  "f": "text",
  "x-fortran": "text",
  "f77": "text",
  "f90": "text",
  "fdf": "application",
  "vnd.fdf": "application",
  "fif": "image",
  "fractals": "application",
  "fli": "video",
  "x-fli": "video",
  "flo": "image",
  "florian": "image",
  "flx": "text",
  "vnd.fmi.flexstor": "text",
  "fmf": "video",
  "x-atomic3d-feature": "video",
  "for": "text",
  "fpx": "image",
  "vnd.fpx": "image",
  "vnd.net-fpx": "image",
  "frl": "application",
  "freeloader": "application",
  "funk": "audio",
  "make": "audio",
  "g": "text",
  "g3": "image",
  "g3fax": "image",
  "gif": "image",
  "gl": "video",
  "x-gl": "video",
  "gsd": "audio",
  "x-gsm": "audio",
  "gsm": "audio",
  "gsp": "application",
  "x-gsp": "application",
  "gss": "application",
  "x-gss": "application",
  "gtar": "application",
  "x-gtar": "application",
  "gz": "application",
  "x-compressed": "application",
  "x-gzip": "multipart",
  "gzip": "multipart",
  "h": "text",
  "x-h": "text",
  "hdf": "application",
  "x-hdf": "application",
  "help": "application",
  "x-helpfile": "application",
  "hgl": "application",
  "vnd.hp-hpgl": "application",
  "hh": "text",
  "hlb": "text",
  "x-script": "text",
  "hlp": "application",
  "x-winhelp": "application",
  "hpg": "application",
  "hpgl": "application",
  "hqx": "application",
  "binhex": "application",
  "binhex4": "application",
  "mac-binhex": "application",
  "mac-binhex40": "application",
  "x-binhex40": "application",
  "x-mac-binhex40": "application",
  "hta": "application",
  "htc": "text",
  "x-component": "text",
  "htm": "text",
  "htmls": "text",
  "htt": "text",
  "webviewhtml": "text",
  "htx": "text",
  "ice": "x-conference",
  "x-cooltalk": "x-conference",
  "ico": "image",
  "x-icon": "image",
  "idc": "text",
  "ief": "image",
  "iefs": "image",
  "iges": "model",
  "igs": "model",
  "ima": "application",
  "x-ima": "application",
  "imap": "application",
  "x-httpd-imap": "application",
  "inf": "application",
  "ins": "application",
  "x-internett-signup": "application",
  "ip": "application",
  "x-ip2": "application",
  "isu": "video",
  "x-isvideo": "video",
  "it": "audio",
  "iv": "application",
  "x-inventor": "application",
  "ivr": "i-world",
  "i-vrml": "i-world",
  "ivy": "application",
  "x-livescreen": "application",
  "jam": "audio",
  "x-jam": "audio",
  "jav": "text",
  "x-java-source": "text",
  "jcm": "application",
  "x-java-commerce": "application",
  "jfif": "image",
  "jpeg": "image",
  "pjpeg": "image",
  "jfif-tbnl": "image",
  "jpe": "image",
  "jpg": "image",
  "jps": "image",
  "x-jps": "image",
  "js": "text",
  "x-javascript": "application",
  "javascript": "text",
  "ecmascript": "text",
  "jut": "image",
  "jutvision": "image",
  "kar": "music",
  "midi": "x-music",
  "x-karaoke": "music",
  "ksh": "text",
  "x-ksh": "application",
  "x-script.ksh": "text",
  "la": "audio",
  "nspaudio": "audio",
  "x-nspaudio": "audio",
  "lam": "audio",
  "x-liveaudio": "audio",
  "latex": "application",
  "x-latex": "application",
  "lha": "application",
  "x-lha": "application",
  "lhx": "application",
  "list": "text",
  "lma": "audio",
  "log": "text",
  "lsp": "text",
  "x-lisp": "application",
  "x-script.lisp": "text",
  "lst": "text",
  "lsx": "text",
  "x-la-asf": "text",
  "ltx": "application",
  "lzh": "application",
  "x-lzh": "application",
  "lzx": "application",
  "x-lzx": "application",
  "m": "text",
  "x-m": "text",
  "m1v": "video",
  "mpeg": "audio",
  "m2a": "audio",
  "m2v": "video",
  "m3u": "audio",
  "x-mpequrl": "audio",
  "man": "application",
  "x-troff-man": "application",
  "map": "application",
  "x-navimap": "application",
  "mar": "text",
  "mbd": "application",
  "mbedlet": "application",
  "mc$": "application",
  "x-magic-cap-package-1.0": "application",
  "mcd": "application",
  "mcad": "application",
  "x-mathcad": "application",
  "mcf": "text",
  "vasa": "image",
  "mcp": "application",
  "netmc": "application",
  "me": "application",
  "x-troff-me": "application",
  "mht": "message",
  "rfc822": "message",
  "mhtml": "message",
  "mid": "audio",
  "x-midi": "x-music",
  "x-mid": "audio",
  "crescendo": "music",
  "mif": "application",
  "x-frame": "application",
  "x-mif": "application",
  "mjf": "audio",
  "x-vnd.audioexplosion.mjuicemediafile": "audio",
  "mjpg": "video",
  "x-motion-jpeg": "video",
  "mm": "application",
  "base64": "application",
  "x-meme": "application",
  "mme": "application",
  "mod": "audio",
  "x-mod": "audio",
  "moov": "video",
  "quicktime": "video",
  "mov": "video",
  "movie": "xgl",
  "x-sgi-movie": "video",
  "mp2": "video",
  "x-mpeg": "video",
  "x-mpeq2a": "video",
  "mp3": "video",
  "mpeg3": "audio",
  "x-mpeg-3": "audio",
  "mpa": "video",
  "mpc": "application",
  "x-project": "application",
  "mpe": "video",
  "mpg": "video",
  "mpga": "audio",
  "mpp": "application",
  "vnd.ms-project": "application",
  "mpt": "application",
  "mpv": "application",
  "mpx": "application",
  "mrc": "application",
  "marc": "application",
  "ms": "application",
  "x-troff-ms": "application",
  "mv": "video",
  "my": "audio",
  "mzz": "application",
  "x-vnd.audioexplosion.mzz": "application",
  "nap": "image",
  "naplps": "image",
  "nc": "application",
  "ncm": "application",
  "vnd.nokia.configuration-message": "application",
  "nif": "image",
  "x-niff": "image",
  "niff": "image",
  "nix": "application",
  "x-mix-transfer": "application",
  "nsc": "application",
  "x-conference": "application",
  "nvd": "application",
  "x-navidoc": "application",
  "o": "application",
  "oda": "application",
  "omc": "application",
  "x-omc": "application",
  "omcd": "application",
  "x-omcdatamaker": "application",
  "omcr": "application",
  "x-omcregerator": "application",
  "p": "text",
  "x-pascal": "text",
  "p10": "application",
  "pkcs10": "application",
  "x-pkcs10": "application",
  "p12": "application",
  "pkcs-12": "application",
  "x-pkcs12": "application",
  "p7a": "application",
  "x-pkcs7-signature": "application",
  "p7c": "application",
  "pkcs7-mime": "application",
  "x-pkcs7-mime": "application",
  "p7m": "application",
  "p7r": "application",
  "x-pkcs7-certreqresp": "application",
  "p7s": "application",
  "pkcs7-signature": "application",
  "part": "application",
  "pro_eng": "application",
  "pas": "text",
  "pascal": "text",
  "pbm": "image",
  "x-portable-bitmap": "image",
  "pcl": "application",
  "vnd.hp-pcl": "application",
  "x-pcl": "application",
  "pct": "image",
  "x-pict": "image",
  "pcx": "image",
  "x-pcx": "image",
  "pdb": "chemical",
  "x-pdb": "chemical",
  "pdf": "application",
  "pfunk": "audio",
  "make.my.funk": "audio",
  "pgm": "image",
  "x-portable-graymap": "image",
  "x-portable-greymap": "image",
  "pic": "image",
  "pict": "image",
  "pkg": "application",
  "x-newton-compatible-pkg": "application",
  "pko": "application",
  "vnd.ms-pki.pko": "application",
  "pl": "text",
  "x-script.perl": "text",
  "plx": "application",
  "x-pixclscript": "application",
  "pm": "text",
  "x-xpixmap": "image",
  "x-script.perl-module": "text",
  "pm4": "application",
  "x-pagemaker": "application",
  "pm5": "application",
  "png": "image",
  "pnm": "image",
  "x-portable-anymap": "image",
  "pot": "application",
  "mspowerpoint": "application",
  "vnd.ms-powerpoint": "application",
  "pov": "model",
  "x-pov": "model",
  "ppa": "application",
  "ppm": "image",
  "x-portable-pixmap": "image",
  "pps": "application",
  "ppt": "application",
  "powerpoint": "application",
  "x-mspowerpoint": "application",
  "ppz": "application",
  "pre": "application",
  "x-freelance": "application",
  "prt": "application",
  "ps": "application",
  "psd": "application",
  "pvu": "paleovu",
  "x-pv": "paleovu",
  "pwz": "application",
  "py": "text",
  "x-script.phyton": "text",
  "pyc": "application",
  "x-bytecode.python": "application",
  "qcp": "audio",
  "vnd.qcelp": "audio",
  "qd3": "x-world",
  "qd3d": "x-world",
  "qif": "image",
  "x-quicktime": "image",
  "qt": "video",
  "qtc": "video",
  "x-qtc": "video",
  "qti": "image",
  "qtif": "image",
  "ra": "audio",
  "x-pn-realaudio": "audio",
  "x-pn-realaudio-plugin": "audio",
  "x-realaudio": "audio",
  "ram": "audio",
  "ras": "image",
  "x-cmu-raster": "image",
  "cmu-raster": "image",
  "rast": "image",
  "rexx": "text",
  "x-script.rexx": "text",
  "rf": "image",
  "vnd.rn-realflash": "image",
  "rgb": "image",
  "x-rgb": "image",
  "rm": "audio",
  "vnd.rn-realmedia": "application",
  "rmi": "audio",
  "rmm": "audio",
  "rmp": "audio",
  "rng": "application",
  "ringing-tones": "application",
  "vnd.nokia.ringing-tone": "application",
  "rnx": "application",
  "vnd.rn-realplayer": "application",
  "roff": "application",
  "x-troff": "application",
  "rp": "image",
  "vnd.rn-realpix": "image",
  "rpm": "audio",
  "rt": "text",
  "richtext": "text",
  "vnd.rn-realtext": "text",
  "rtf": "application",
  "x-rtf": "application",
  "rtx": "text",
  "rv": "video",
  "vnd.rn-realvideo": "video",
  "s": "text",
  "s3m": "audio",
  "saveme": "application",
  "sbk": "application",
  "x-tbook": "application",
  "scm": "video",
  "x-lotusscreencam": "application",
  "x-script.guile": "text",
  "x-script.scheme": "text",
  "x-scm": "video",
  "sdml": "text",
  "sdp": "application",
  "x-sdp": "application",
  "sdr": "application",
  "sounder": "application",
  "sea": "application",
  "x-sea": "application",
  "set": "application",
  "sgm": "text",
  "sgml": "text",
  "x-sgml": "text",
  "sh": "text",
  "x-sh": "application",
  "x-shar": "application",
  "x-script.sh": "text",
  "shar": "application",
  "shtml": "text",
  "x-server-parsed-html": "text",
  "sid": "audio",
  "x-psid": "audio",
  "sit": "application",
  "x-sit": "application",
  "x-stuffit": "application",
  "skd": "application",
  "x-koan": "application",
  "skm": "application",
  "skp": "application",
  "skt": "application",
  "sl": "application",
  "x-seelogo": "application",
  "smi": "application",
  "smil": "application",
  "snd": "audio",
  "x-adpcm": "audio",
  "sol": "application",
  "solids": "application",
  "spc": "text",
  "x-pkcs7-certificates": "application",
  "x-speech": "text",
  "spl": "application",
  "futuresplash": "application",
  "spr": "application",
  "x-sprite": "application",
  "sprite": "application",
  "src": "application",
  "x-wais-source": "application",
  "ssi": "text",
  "ssm": "application",
  "streamingmedia": "application",
  "sst": "application",
  "vnd.ms-pki.certstore": "application",
  "step": "application",
  "stl": "application",
  "sla": "application",
  "vnd.ms-pki.stl": "application",
  "x-navistyle": "application",
  "stp": "application",
  "sv4cpio": "application",
  "x-sv4cpio": "application",
  "sv4crc": "application",
  "x-sv4crc": "application",
  "svf": "image",
  "svr": "x-world",
  "x-world": "application",
  "x-svr": "x-world",
  "swf": "application",
  "x-shockwave-flash": "application",
  "t": "application",
  "talk": "text",
  "tar": "application",
  "x-tar": "application",
  "tbk": "application",
  "toolbook": "application",
  "tcl": "text",
  "x-tcl": "application",
  "x-script.tcl": "text",
  "tcsh": "text",
  "x-script.tcsh": "text",
  "tex": "application",
  "x-tex": "application",
  "texi": "application",
  "x-texinfo": "application",
  "texinfo": "application",
  "text": "text",
  "tgz": "application",
  "gnutar": "application",
  "tif": "image",
  "tiff": "image",
  "x-tiff": "image",
  "tr": "application",
  "tsi": "audio",
  "tsp-audio": "audio",
  "tsp": "audio",
  "dsptype": "application",
  "tsplayer": "audio",
  "tsv": "text",
  "tab-separated-values": "text",
  "turbot": "image",
  "txt": "text",
  "uil": "text",
  "x-uil": "text",
  "uni": "text",
  "uri-list": "text",
  "unis": "text",
  "unv": "application",
  "i-deas": "application",
  "uri": "text",
  "uris": "text",
  "ustar": "multipart",
  "x-ustar": "multipart",
  "uu": "text",
  "x-uuencode": "text",
  "uue": "text",
  "vcd": "application",
  "x-cdlink": "application",
  "vcs": "text",
  "x-vcalendar": "text",
  "vda": "application",
  "vdo": "video",
  "vew": "application",
  "groupwise": "application",
  "viv": "video",
  "vivo": "video",
  "vnd.vivo": "video",
  "vmd": "application",
  "vocaltec-media-desc": "application",
  "vmf": "application",
  "vocaltec-media-file": "application",
  "voc": "audio",
  "x-voc": "audio",
  "vos": "video",
  "vosaic": "video",
  "vox": "audio",
  "voxware": "audio",
  "vqe": "audio",
  "x-twinvq-plugin": "audio",
  "vqf": "audio",
  "x-twinvq": "audio",
  "vql": "audio",
  "vrml": "model",
  "x-vrml": "x-world",
  "vrt": "x-world",
  "x-vrt": "x-world",
  "vsd": "application",
  "x-visio": "application",
  "vst": "application",
  "vsw": "application",
  "w60": "application",
  "wordperfect6.0": "application",
  "w61": "application",
  "wordperfect6.1": "application",
  "w6w": "application",
  "wav": "audio",
  "x-wav": "audio",
  "wb1": "application",
  "x-qpro": "application",
  "wbmp": "image",
  "vnd.wap.wbmp": "image",
  "web": "application",
  "vnd.xara": "application",
  "wiz": "application",
  "wk1": "application",
  "x-123": "application",
  "wmf": "windows",
  "metafile": "windows",
  "wml": "text",
  "vnd.wap.wml": "text",
  "wmlc": "application",
  "vnd.wap.wmlc": "application",
  "wmls": "text",
  "vnd.wap.wmlscript": "text",
  "wmlsc": "application",
  "vnd.wap.wmlscriptc": "application",
  "word": "application",
  "wp": "application",
  "wordperfect": "application",
  "wp5": "application",
  "wp6": "application",
  "wpd": "application",
  "x-wpwin": "application",
  "wq1": "application",
  "x-lotus": "application",
  "wri": "application",
  "mswrite": "application",
  "x-wri": "application",
  "wrl": "x-world",
  "wrz": "x-world",
  "wsc": "text",
  "scriplet": "text",
  "wsrc": "application",
  "wtk": "application",
  "x-wintalk": "application",
  "xbm": "image",
  "x-xbitmap": "image",
  "x-xbm": "image",
  "xdr": "video",
  "x-amt-demorun": "video",
  "xgz": "xgl",
  "drawing": "xgl",
  "xif": "image",
  "vnd.xiff": "image",
  "xl": "application",
  "excel": "application",
  "xla": "application",
  "x-excel": "application",
  "x-msexcel": "application",
  "xlb": "application",
  "vnd.ms-excel": "application",
  "xlc": "application",
  "xld": "application",
  "xlk": "application",
  "xll": "application",
  "xlm": "application",
  "xls": "application",
  "xlt": "application",
  "xlv": "application",
  "xlw": "application",
  "xm": "audio",
  "xml": "text",
  "xmz": "xgl",
  "xpix": "application",
  "x-vnd.ls-xpix": "application",
  "xpm": "image",
  "x-png": "image",
  "xsr": "video",
  "x-amt-showrun": "video",
  "xwd": "image",
  "x-xwd": "image",
  "x-xwindowdump": "image",
  "xyz": "chemical",
  "z": "application",
  "x-compress": "application",
  "zip": "multipart",
  "x-zip-compressed": "application",
  "x-zip": "multipart",
  "zoo": "application",
  "zsh": "text",
  "x-script.zsh": "text"
}


 
  // decryption in back directory....

class MediaHandler {
  //
  constructor(conf) {
    //
    this.media_dir = conf.media_dir
    this.entries_dir = conf.entries_dir
    this.default_repo = DEFAULT_P2P_REPO
    //
    this.link_manager = false
    //
    this.media_types = conf && conf.media_types ? conf.media_types : g_media_types
    if ( typeof conf.media_encryption_selection === 'object' ) {
      for ( let mtype in this.media_types ) {
        let sel_mtype =  conf.media_encryption_selection[mtype]
        if ( sel_mtype && (typeof sel_mtype.encrypted !== "boolean") ) {
          this.media_types[mtype].encrypted = sel_mtype.encrypted
        }
      }
    } 
    this.repository = false
    if ( this.media_dir ) {
      for ( let mt in this.media_types ) {
        this.media_types[mt].dir =  this.media_dir.replace('$media_type',mt)
      }  
    }    //
  }

  async init_repository(conf) {
    if ( conf.default_p2p_repo !== undefined ) {
      this.default_repo = conf.default_p2p_repo       // config `default_p2p_repo` becomes member `default_repo`
    }
    if ( ( conf.accepted_repos !== undefined ) && (Array.isArray(conf.accepted_repos) ) ) {
      this.accepted_repos = conf.accepted_repos
      if ( this.accepted_repos.indexOf(this.default_repo) < 0 ) {
        this.accepted_repos.push(this.default_repo)
      }
    } else {
      this.accepted_repos = [this.default_repo]   // if the accepted repos are not listed, this becomes a list of one
    }
    this.repository = new Repository(conf.repos,this.accepted_repos)
    if ( this.link_manager ) {
      this.repository.set_link_mamagers(conf,this.link_manager)
    }
    await this.repository.init_repos()
  }


  /**
   * set_link_manager
   * 
   * @param {object} conf 
   * @param {object} link_m 
   */
  set_link_manager(conf,link_m) {
    this.link_manager = link_m
    this.repo_link_conf = conf
  }


  is_accepted_rep(repo) {
    let i = this.accepted_repos.indexOf(repo)
    return ( i >= 0 )
  }


  supported_media_type(media_type) {
    return (this.media_types[media_type] !== undefined)
  }

  nearest_media_type(media_type) {
    let possible = types_to_general_media_types[media_type]
    if ( possible === undefined ) return("text")
    if ( this.supported_media_type(possible) ) {
      return possible
    }
    return "text"
  }

  // _media_storage
  // FOR IMAGE AND STREAM
  //      media_name is for local disk storage only...
  //    What goes to the ipfs like repository is the encode blob of data. The same as the local file...
  //

  async _media_storage(repo_kind,media_name,media_type,enc_blob) {
      //
      try {
        let media_dir = this.media_types[media_type].dir
        let out_file = media_dir + media_name
        // store to the local drive
        let store_local = this.media_types[media_type].store_local
        if ( store_local ) {
          fs.writeFileSync(out_file,enc_blob)   // write binary encrypted data
        }
        // store to the local repo
        let store_repo = this.media_types[media_type].store_repo
        if ( store_repo && this.repository ) {
          // add locally to the p2p subsytem... -> this will be pinned in the persistence manager...
          const repo_id = await this.repository.add(repo_kind,enc_blob)  // put the same data in the repo (com and P2P storage)
          if ( repo_id !== false ) {
            return {
              "protocol" : repo_kind,
              "id" : repo_id
            }  
          }
        }
        return true
      } catch (e) {
        return false
      }
      //
  }

  storable(source) {      // turn data into something that can be processed further down the line
    let blob_data = source.blob_url
    delete source.blob_url  // this is only used to go from the interface to storage 
    //
    let bdata_parts = blob_data.split(',')
    let blob_bytes = bdata_parts[1]
    let blob = Buffer.from(blob_bytes, 'base64');
    return blob
  }

  // store_media
  //      ---- store the actual data... and edit the fields of the meta data object
  //      ---- this is the api interface for storing across the repository bridge from here.
  async store_media(blob,media,media_name,media_type) {
    // 
    if ( media_type in this.media_types ) {
      let protocol = media.protocol
      if ( !this.is_accepted_rep(repo) ) {
        protocol = this.default_repo
      }
      let result = await this._media_storage(protocol,media_name,media_type,blob)
      if ( typeof result === 'boolean' ) {
        return result
      } else {
        media.protocol = result.protocol
        media[media.protocol] = result.id
      }
      return true
    }
    return false
  }

}


// for external global use (not done as a static of the class...)
function nearest_media_type(media_type) {
  let possible = types_to_general_media_types[media_type]
  if ( possible === undefined ) return("text")
  if ( g_media_types[possible] !== undefined ) {
    return possible
  }
  return "text"
}


module.exports = MediaHandler
module.nearest_media_type = nearest_media_type