fileserver: Enable browse pagination with offset parameter (#3542)

* Update browse.go

* Update browselisting.go

* Update browsetpl.go

* fix linter err

* Update modules/caddyhttp/fileserver/browse.go

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

* Update modules/caddyhttp/fileserver/browselisting.go

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

* Update browsetpl.go

change from -> offset

* Update browse.go

* Update browselisting.go

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

3 files changed, 27 insertions, 14 deletions

diff --git a/modules/caddyhttp/fileserver/browse.go b/modules/caddyhttp/fileserver/browse.go
index e5e137f..3fecad9 100644
--- a/modules/caddyhttp/fileserver/browse.go
+++ b/modules/caddyhttp/fileserver/browse.go
@@ -106,6 +106,7 @@ func (fsrv *FileServer) browseApplyQueryParams(w http.ResponseWriter, r *http.Re
 	sortParam := r.URL.Query().Get("sort")
 	orderParam := r.URL.Query().Get("order")
 	limitParam := r.URL.Query().Get("limit")
+	offsetParam := r.URL.Query().Get("offset")
 
 	// first figure out what to sort by
 	switch sortParam {
@@ -130,7 +131,7 @@ func (fsrv *FileServer) browseApplyQueryParams(w http.ResponseWriter, r *http.Re
 	}
 
 	// finally, apply the sorting and limiting
-	listing.applySortAndLimit(sortParam, orderParam, limitParam)
+	listing.applySortAndLimit(sortParam, orderParam, limitParam, offsetParam)
 }
 
 func (fsrv *FileServer) browseWriteJSON(listing browseListing) (*bytes.Buffer, error) {
diff --git a/modules/caddyhttp/fileserver/browselisting.go b/modules/caddyhttp/fileserver/browselisting.go
index 9c7c4a2..cebfe8f 100644
--- a/modules/caddyhttp/fileserver/browselisting.go
+++ b/modules/caddyhttp/fileserver/browselisting.go
@@ -101,6 +101,9 @@ type browseListing struct {
 
 	// If ≠0 then Items have been limited to that many elements.
 	ItemsLimitedTo int
+
+	// If ≠0 then Items starting from that many elements.
+	ItemOffset int
 }
 
 // Breadcrumbs returns l.Path where every element maps
@@ -131,7 +134,7 @@ func (l browseListing) Breadcrumbs() []crumb {
 	return result
 }
 
-func (l *browseListing) applySortAndLimit(sortParam, orderParam, limitParam string) {
+func (l *browseListing) applySortAndLimit(sortParam, orderParam, limitParam string, offsetParam string) {
 	l.Sort = sortParam
 	l.Order = orderParam
 
@@ -159,8 +162,17 @@ func (l *browseListing) applySortAndLimit(sortParam, orderParam, limitParam stri
 		}
 	}
 
+	if offsetParam != "" {
+		offset, _ := strconv.Atoi(offsetParam)
+		if offset > 0 && offset <= len(l.Items) {
+			l.Items = l.Items[offset:]
+			l.ItemOffset = offset
+		}
+	}
+
 	if limitParam != "" {
 		limit, _ := strconv.Atoi(limitParam)
+
 		if limit > 0 && limit <= len(l.Items) {
 			l.Items = l.Items[:limit]
 			l.ItemsLimitedTo = limit
diff --git a/modules/caddyhttp/fileserver/browsetpl.go b/modules/caddyhttp/fileserver/browsetpl.go
index 567e8dd..6415d59 100644
--- a/modules/caddyhttp/fileserver/browsetpl.go
+++ b/modules/caddyhttp/fileserver/browsetpl.go
@@ -296,37 +296,37 @@ footer {
 						<th></th>
 						<th>
 							{{- if and (eq .Sort "namedirfirst") (ne .Order "desc")}}
-							<a href="?sort=namedirfirst&order=desc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}" class="icon"><svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg></a>
+							<a href="?sort=namedirfirst&order=desc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}" class="icon"><svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg></a>
 							{{- else if and (eq .Sort "namedirfirst") (ne .Order "asc")}}
-							<a href="?sort=namedirfirst&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}" class="icon"><svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
+							<a href="?sort=namedirfirst&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}" class="icon"><svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
 							{{- else}}
-							<a href="?sort=namedirfirst&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}" class="icon sort"><svg class="top" width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg><svg class="bottom" width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
+							<a href="?sort=namedirfirst&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}" class="icon sort"><svg class="top" width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg><svg class="bottom" width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
 							{{- end}}
 							
 							{{- if and (eq .Sort "name") (ne .Order "desc")}}
-							<a href="?sort=name&order=desc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Name <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg></a>
+							<a href="?sort=name&order=desc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Name <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg></a>
 							{{- else if and (eq .Sort "name") (ne .Order "asc")}}
-							<a href="?sort=name&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Name <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
+							<a href="?sort=name&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Name <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
 							{{- else}}
-							<a href="?sort=name&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Name</a>
+							<a href="?sort=name&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Name</a>
 							{{- end}}
 						</th>
 						<th>
 							{{- if and (eq .Sort "size") (ne .Order "desc")}}
-							<a href="?sort=size&order=desc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Size <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg></a>
+							<a href="?sort=size&order=desc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Size <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg></a>
 							{{- else if and (eq .Sort "size") (ne .Order "asc")}}
-							<a href="?sort=size&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Size <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
+							<a href="?sort=size&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Size <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
 							{{- else}}
-							<a href="?sort=size&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Size</a>
+							<a href="?sort=size&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Size</a>
 							{{- end}}
 						</th>
 						<th class="hideable">
 							{{- if and (eq .Sort "time") (ne .Order "desc")}}
-							<a href="?sort=time&order=desc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Modified <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg></a>
+							<a href="?sort=time&order=desc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Modified <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#up-arrow"></use></svg></a>
 							{{- else if and (eq .Sort "time") (ne .Order "asc")}}
-							<a href="?sort=time&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Modified <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
+							<a href="?sort=time&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Modified <svg width="1em" height=".5em" version="1.1" viewBox="0 0 12.922194 6.0358899"><use xlink:href="#down-arrow"></use></svg></a>
 							{{- else}}
-							<a href="?sort=time&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}">Modified</a>
+							<a href="?sort=time&order=asc{{if ne 0 .ItemsLimitedTo}}&limit={{.ItemsLimitedTo}}{{end}}{{if ne 0 .ItemOffset}}&offset={{.ItemOffset}}{{end}}">Modified</a>
 							{{- end}}
 						</th>
 						<th class="hideable"></th>