Upload images to Imgur from Mathematica

Question

Here\'s a challenge to all mathematica tag followers. Let\'s make it a lot more convenient to insert images into SO post from Mathematica by creating an imgur

Answer 1

Note: Get an ready-made palette with this functionality here.

---

Arnoud's solution got me excited and impatient, so here's an improvement to it. I couldn't have done this without studying his code. This version seems to be somewhat more reliable and less prone to timeout errors, but to be honest, I know no Java at all, so any improvements are welcome.

Most importantly: this version uploads to stack.imgur.com directly, so it's safe to use here on StackOverflow, without having to worry that uploaded images will disappear after a while.

I provide three functions:

• stackImage uploads the expression, exported as PNG, and returns the URL
• stackMarkdown returns the markdown, ready to be copied
• stackCopyMarkdown copies the markdown to the clipboard

Next step: create a palette button that does this automatically for the selected graphic in the notebook. Improvements to the code are very welcome.

---

Needs["JLink`"]


stackImage::httperr = "Server returned respose code: `1`";
stackImage::err = "Server returner error: `1`";

stackImage[g_] :=
 Module[
  {getVal, url, client, method, data, partSource, part, entity, code, 
   response, error, result},

  (* this function attempts to parse the response fro the SO server *)
  getVal[res_, key_String] :=
   With[{k = "var " <> key <> " = "},
    StringTrim[
     First@StringCases[First@Select[res, StringMatchQ[#, k ~~ ___] &], 
       k ~~ v___ ~~ ";" :> v],
     "'"]
    ];

  data = ExportString[g, "PNG"];

  JavaBlock[
    url = "https://stackoverflow.com/upload/image";
    client = JavaNew["org.apache.commons.httpclient.HttpClient"];
    method = JavaNew["org.apache.commons.httpclient.methods.PostMethod", url];
    partSource = JavaNew["org.apache.commons.httpclient.methods.multipart.ByteArrayPartSource", "mmagraphics.png", MakeJavaObject[data]@toCharArray[]];
    part = JavaNew["org.apache.commons.httpclient.methods.multipart.FilePart", "name", partSource];
    part@setContentType["image/png"];
    entity = JavaNew["org.apache.commons.httpclient.methods.multipart.MultipartRequestEntity", {part}, method@getParams[]];
    method@setRequestEntity[entity];
    code = client@executeMethod[method];
    response = method@getResponseBodyAsString[];
  ]

  If[code =!= 200, Message[stackImage::httperr, code]; Return[$Failed]];
  response = StringTrim /@ StringSplit[response, "\n"];

  error = getVal[response, "error"];
  result = getVal[response, "result"];
  If[StringMatchQ[result, "http*"],
   result,
   Message[stackImage::err, error]; $Failed]
  ]


stackMarkdown[g_] := "![Mathematica graphics](" <> stackImage[g] <> ")"


stackCopyMarkdown[g_] := Module[{nb, markdown},
  markdown = Check[stackMarkdown[g], $Failed];
  If[markdown =!= $Failed,
   nb = NotebookCreate[Visible -> False];
   NotebookWrite[nb, Cell[markdown, "Text"]];
   SelectionMove[nb, All, Notebook];
   FrontEndTokenExecute[nb, "Copy"];
   NotebookClose[nb];
   ]
  ]

Update:

Here's a button that will show a preview of the selection and will offer uploading (or cancelling). It requires the previous functions to be defined.

Button["Upload to SO",
 Module[{cell = NotebookRead@InputNotebook[], img},
  If[cell =!= {}, img = Rasterize[cell];
   MessageDialog[
    Column[{"Upload image to StackExchange sites?", 
      img}], {"Upload and copy MarkDown" :> stackCopyMarkdown[img], 
     "Cancel" :> Null}, WindowTitle -> "Upload to StackExchange"]]]]

Unfortunately I can't put the button in a palette (CreatePalette) because the palette dimensions will influence the rasterization. Solutions to this problem are welcome.

Update 2:

Based on the answer to this question, here's a working Windows-only palette button:

button = Button["Upload to SO",
  Module[{sel},
   FrontEndExecute[
    FrontEndToken[FrontEnd`SelectedNotebook[], "CopySpecial", "MGF"]];
   sel = Cases[NotebookGet@ClipboardNotebook[], 
     RasterBox[data_, ___] :> 
      Image[data, "Byte", ColorSpace -> "RGB", Magnification -> 1], 
     Infinity];
   If[sel =!= {},
    With[{img = First[sel]},
     MessageDialog[
      Column[{"Upload image to StackExchange sites?", 
        img}], {"Upload and copy MarkDown" :> stackCopyMarkdown[img], 
       "Cancel" :> Null}, WindowTitle -> "Upload to StackExchange"]
     ]
    ]
   ]
  ]

CreatePalette[button]

Warning: it destroys the clipboard contents even if you click cancel in the preview box.