Implement server /photos routing, get/post functionality #11
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* Add thumbnail functionality * Restructured server, added exif parsing, added fields to Photo * Fix exif value stripping of null character
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The packages that this depends on should be added to the |
| PhotosDirectory: "/var/hotshots", | ||
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| dir, ok := os.LookupEnv("HOTSHOTS_DIR") |
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We probably want to make ListenURL configurable via env var too. Another time.
| defer thumbw.Close() | ||
| defer exifw.Close() | ||
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| mw := io.MultiWriter(photow, thumbw, exifw) |
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This is some fancy stuff I've never seen before
| go GetExif(&xif, exifr, saveErr) | ||
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| wasErrorSaving := false | ||
| for saveProcesses := 0; saveProcesses < 3; saveProcesses++ { |
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I think using a sync.WaitGroup here would be more idiomatic, but this does the job just fine.
| Success bool | ||
| Error string | ||
| URI string | ||
| } |
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We likely want to snake_case all returned JSON fields with some struct tags, but it doesn't matter all that much.
| } | ||
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| func (s *Server) PostPhoto(w http.ResponseWriter, r *http.Request) { | ||
| r.ParseMultipartForm(1 << 23) // 8M max memory |
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Should we up this a bit? Anything up to maybe 20–30 MB would be a reasonable size for an uploaded JPEG, and if we up this a little bit (maybe 32 MB? Go's net/http sets its defaultMaxMemory to that) then we can avoid temp files touching the disk at all. We're not RAM-constrained on the server.
| func GetExif(out *exif.Exif, data io.Reader, saveErr chan error) { | ||
| x, err := exif.Decode(data) | ||
| io.Copy(ioutil.Discard, data) | ||
| if err != nil { |
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Here err is always io.EOF if there is no Exif data in the photo, which causes a POST to /photos to fail. We might want to check for that and just return an empty Exif data. This is not a dealbreaker because any reasonable camera embeds some Exif data.
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Wasn't a requirement for our service that your image had exif data?
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Oh, maybe. That would make sense. It's a requirement now.
| saveErr <- err | ||
| return | ||
| } | ||
| *out = *x |
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This is kinda funky; I think the idiomatic thing to do would be to return the Exif data through a channel vs. C-style passing pointers to functions to modify them.
| saveErr <- err | ||
| return | ||
| } | ||
| *r = img.Bounds() |
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Kinda funky; see my comment on line 187.
| return false | ||
| } | ||
| readErr := unix.Access(serv.cfg.PhotosDirectory, unix.R_OK) | ||
| writeErr := unix.Access(serv.cfg.PhotosDirectory, unix.W_OK) |
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Can this be done with os.Stat()? So we're not relying on OS-specific stuff. (I may want to run Hotshots on my Windows XP SP2 box.)
#3
Implemented Endpoints
GET /photos/- Return array of all photo objects storedPOST /photos/- Upload photoGET /photos/ids/- Return array of all photo id stringsGET /photos/<id>/meta/- Return photo object for the given idGET /photos/<id>/image.jpg- Return jpg image data for the given idGET /photos/<id>/thumb.jpg- Return jpg thumbnail data for the given id (created on upload)Files:
servers/server.go- Contains server handling and setupservers/request.go- Contains request handling logic for each routeservers/photo.go- Contains photo metadata struct, photo processing logicservers/helpers.go- Contains misc. logic