ae843e42c15f576fcbf9cc4a3671e615cf905a96
jcasper
  Wed Jul 6 12:45:04 2016 -0700
Additional configuration options for session thumbnail creation and examples for same, refs #17469

diff --git src/hg/lib/sessionThumbnail.c src/hg/lib/sessionThumbnail.c
index 2bc60f1..f7c2e9b 100644
--- src/hg/lib/sessionThumbnail.c
+++ src/hg/lib/sessionThumbnail.c
@@ -1,44 +1,67 @@
 /* sessionThumbnail - get the filename, filesystem path, and web URI
  * for the thumbnail image associated with a session.
  *
  * Copyright (C) 2016 The Regents of the University of California 
  * See README in this or parent directory for licensing information. */
 
 #include "common.h"
 #include "dystring.h"
 #include "hash.h"
 #include "trashDir.h"
+#include "hgConfig.h"
+
+#define IMGDIR_OPTION "sessionThumbnail.imgDir"
+#define WEBPATH_OPTION "sessionThumbnail.webPath"
 
 void sessionBuildThumbnailFilePaths(struct tempName *thumbnailPath, char *userIdx,
                                   char *encSessionName, char *firstUse)
 /* Populate thumbnailPath with paths to the thumbnail image for the specified session.
  * The basename of the thumbnail image is based on several pieces of data on the session:
  * userIdx is a presumed unique ID suitable for being part of a filename,
  * encSessionName is the cgi-encoded session name,
  * and firstUse is the mysql-formatted time string for the session's creation date.
  * Leaks memory via a dyString. */
 {
 struct dyString *base = dyStringCreate("hgPS_%s_%u_%ld",
     userIdx, hashString(encSessionName), dateToSeconds(firstUse, "%Y-%m-%d %T"));
+char *imgDir = cfgOption(IMGDIR_OPTION);
+char *webPath = cfgOption(WEBPATH_OPTION);
+if (imgDir != NULL && webPath != NULL)
+    {
+    makeDirsOnPath(imgDir);
+    safef(thumbnailPath->forCgi, sizeof(thumbnailPath->forCgi), "%s%s%s.png", imgDir,
+        lastChar(thumbnailPath->forCgi) == '/' ? "" : "/",
+        dyStringContents(base));
+    safef(thumbnailPath->forHtml, sizeof(thumbnailPath->forCgi), "%s%s%s.png", imgDir,
+        lastChar(thumbnailPath->forCgi) == '/' ? "" : "/",
+        dyStringContents(base));
+    }
+else if (imgDir != NULL || webPath != NULL)
+    {
+    errAbort("Error with session thumbnail path configuration.  "
+        "Either both %s and %s should be set in hg.conf or neither.",
+        IMGDIR_OPTION, WEBPATH_OPTION);
+    }
+else
     trashDirReusableFile(thumbnailPath, "hgPS", dyStringContents(base), ".png");
 }
 
 char *sessionThumbnailFilePath(char *userIdx, char *encSessionName,
                                char *firstUse)
 /* Returns the path to the thumbnail image of the specified session as seen by CGIs.
  * Result must be freed. */
 {
 struct tempName thumbnailPath;
 sessionBuildThumbnailFilePaths(&thumbnailPath, userIdx, encSessionName, firstUse);
 return cloneString(thumbnailPath.forCgi);
 }
 
 char *sessionThumbnailFileUri(char *userIdx, char *encSessionName,
                               char *firstUse)
 /* Returns the path to the thumbnail image of the specified session as seen by web viewers.
  * Result must be freed. */
 {
 struct tempName thumbnailPath;
 sessionBuildThumbnailFilePaths(&thumbnailPath, userIdx, encSessionName, firstUse);
 return cloneString(thumbnailPath.forHtml);
 }