<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><blockquote type="cite" class="">On Aug 8, 2016, at 4:32 PM, Kevin Ballard <<a href="mailto:kevin@sb.org" class="">kevin@sb.org</a>> wrote:<br class=""></blockquote><div><blockquote type="cite" class=""><br class="Apple-interchange-newline"><div class=""><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">The documentation is wrong (for Swift).<br class=""></div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">For file URLs, this method returns true/false without throwing an error (at least, if the file doesn't exist there's no error; I don't know if there are conditions that would cause an error to be returned).<br class=""></div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">For non-file URLs this method throws an error.<br class=""></div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">The bit about "For other URL types, false is returned" is written for Obj-C, where you can completely disregard the error. You can't disregard the error in Swift, so it doesn't apply (though you can use try? and treat a nil value the same as false)</div></div></blockquote></div><br class=""><div class="">In my testing, this does not appear to be correct; it actually seems to throw an error in both cases. For a file URL pointing to a file that doesn’t exist, it throws NSFileReadNoSuchFileError, and for an HTTP URL, it throws NSFileNoSuchFileError. This further causes me to question the purpose of having the method return a boolean.</div><div class=""><br class=""></div><div class="">Here’s the code:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">import</span><span style="font-variant-ligatures: no-common-ligatures" class=""> Foundation</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; min-height: 13px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">let</span><span style="font-variant-ligatures: no-common-ligatures" class=""> fileURL = </span><span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">URL</span><span style="font-variant-ligatures: no-common-ligatures" class="">(fileURLWithPath: </span><span style="font-variant-ligatures: no-common-ligatures; color: #d12f1b" class="">"/asdfasdfasdf"</span><span style="font-variant-ligatures: no-common-ligatures" class="">)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">let</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> httpURL = </span><span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">URL</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(string: </span><span style="font-variant-ligatures: no-common-ligatures" class="">"<a href="http://asdfasdfasdf.com/asdfasdfasdf" class="">http://asdfasdfasdf.com/asdfasdfasdf</a>"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)!</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; min-height: 13px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">do</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(61, 29, 129);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">if</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">try</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">fileURL</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures" class="">checkResourceIsReachable</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">() {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #3d1d81" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"file URL is reachable"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> } </span><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">else</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #3d1d81" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"file URL returned false"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(187, 44, 162);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">} </span><span style="font-variant-ligatures: no-common-ligatures" class="">catch</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #3d1d81" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"file URL threw error: </span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">\</span><span style="font-variant-ligatures: no-common-ligatures" class="">(</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">error</span><span style="font-variant-ligatures: no-common-ligatures" class="">)"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; min-height: 13px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""></span><br class=""></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">do</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(61, 29, 129);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">if</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">try</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">httpURL</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">.</span><span style="font-variant-ligatures: no-common-ligatures" class="">checkResourceIsReachable</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">() {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #3d1d81" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"http URL is reachable"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> } </span><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">else</span><span style="font-variant-ligatures: no-common-ligatures" class=""> {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #3d1d81" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"http URL returned false"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""> }</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(187, 44, 162);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">} </span><span style="font-variant-ligatures: no-common-ligatures" class="">catch</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> {</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span><span style="font-variant-ligatures: no-common-ligatures; color: #3d1d81" class="">print</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"http URL threw error: </span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">\</span><span style="font-variant-ligatures: no-common-ligatures" class="">(</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">error</span><span style="font-variant-ligatures: no-common-ligatures" class="">)"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div><div class=""><br class=""></div><div class="">And the output:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">file URL threw error: Error Domain=NSCocoaErrorDomain Code=260 "The file “asdfasdfasdf” couldn’t be opened because there is no such file." UserInfo={NSURL=<a href="file:///asdfasdfasdf" class="">file:///asdfasdfasdf</a>, NSFilePath=/asdfasdfasdf, NSUnderlyingError=0x100903eb0 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}</b></span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">http URL threw error: Error Domain=NSCocoaErrorDomain Code=4 "The file doesn’t exist."</b></span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">Program ended with exit code: 0</b></span></div></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""><br class=""></b></span></div><div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><span style="font-family: Helvetica; font-size: 12px;" class="">Charles</span></span></div></body></html>