new file mode 100644
--- /dev/null
+++ b/src/event/ngx_event_proxy.c
@@ -0,0 +1,510 @@
+
+#include <ngx_event_proxy.h>
+
+
+int ngx_event_proxy_read_upstream(ngx_event_proxy_t *p)
+{
+    int           n, rc, size;
+    ngx_hunk_t   *h, *nh;
+    ngx_chain_t  *chain, *temp, *entry, *next;
+
+    p->level++;
+
+ngx_log_debug(p->log, "read upstream");
+
+    for ( ;; ) {
+
+        /* use the free hunks if they exist */
+
+        if (p->free_hunks) {
+            chain = p->free_hunks;
+            p->free_hunks = NULL;
+
+ngx_log_debug(p->log, "free hunk: %08X:%d" _ chain->hunk _
+              chain->hunk->end - chain->hunk->last);
+
+        /* allocate a new hunk if it's still allowed */
+
+        } else if (p->allocated < p->max_block_size) {
+            ngx_test_null(h,
+                          ngx_create_temp_hunk(p->pool, p->block_size, 20, 20),
+                          NGX_ERROR);
+
+            p->allocated += p->block_size;
+
+            ngx_test_null(temp, ngx_alloc_chain_entry(p->pool), NGX_ERROR);
+            temp->hunk = h;
+            temp->next = NULL;
+            chain = temp;
+
+ngx_log_debug(p->log, "new hunk: %08X" _ chain->hunk);
+
+        /* use the shadow hunks if they exist */
+
+        } else if (p->shadow_hunks) {
+            chain = p->shadow_hunks;
+            p->shadow_hunks = NULL;
+
+ngx_log_debug(p->log, "shadow hunk: %08X" _ chain->hunk);
+
+        /* if it's allowed then save the incoming hunks to a temporary file,
+           move the saved hunks to a shadow chain,
+           and add the file hunks to an outgoing chain */
+
+        } else if (p->temp_offset < p->max_temp_size) {
+            rc = ngx_event_proxy_write_chain_to_temp_file(p);
+
+ngx_log_debug(p->log, "temp offset: %d" _ p->temp_offset);
+
+            if (rc != NGX_OK) {
+                return rc;
+            }
+
+            chain = p->shadow_hunks;
+            p->shadow_hunks = NULL;
+
+ngx_log_debug(p->log, "new shadow hunk: %08X" _ chain->hunk);
+
+        /* if there're no hunks to read in then disable a level event */
+
+        } else {
+            if (ngx_event_flags & NGX_USE_LEVEL_EVENT) {
+                p->block_upstream = 1;
+            }
+
+            break;
+        }
+
+        n = ngx_recv_chain(p->upstream, chain);
+
+ngx_log_debug(p->log, "recv_chain: %d" _ n);
+
+        if (n == NGX_ERROR) {
+            p->upstream_error = 1;
+            return NGX_ERROR;
+        }
+
+        if (n == NGX_AGAIN) {
+            if (p->upstream->read->blocked) {
+                if (ngx_add_event(p->upstream->read, NGX_READ_EVENT,
+                                               NGX_LEVEL_EVENT) == NGX_ERROR) {
+                    return NGX_ERROR;
+                }
+                p->upstream->read->blocked = 0;
+            }
+
+            return NGX_AGAIN;
+        }
+
+        if (n == 0) {
+            p->free_hunks = chain;
+            p->upstream_eof = 1;
+            p->block_upstream = 0;
+            break;
+        }
+
+        /* move the full hunks to a read chain
+           and the partial filled hunk to a free chain
+           and remove the shadow links for these hunks */
+
+        for (entry = chain; entry && n > 0; entry = next) {
+            next = entry->next;
+            entry->next = NULL;
+
+            if (entry->hunk->shadow) {
+                for (h = entry->hunk->shadow;
+                     (h->type & NGX_HUNK_LAST_SHADOW) == 0;
+                     h = nh)
+                {
+                    nh = h->shadow;
+                    h->shadow = NULL;
+                    h->type &= ~(NGX_HUNK_TEMP
+                                 |NGX_HUNK_IN_MEMORY
+                                 |NGX_HUNK_RECYCLED);
+                }
+
+                h->shadow = NULL;
+                h->type &= ~(NGX_HUNK_TEMP
+                             |NGX_HUNK_IN_MEMORY
+                             |NGX_HUNK_RECYCLED
+                             |NGX_HUNK_LAST_SHADOW);
+                entry->hunk->shadow = NULL;
+            }
+
+            size = entry->hunk->end - entry->hunk->last;
+
+            if (n >= size) {
+                entry->hunk->last = entry->hunk->end;
+
+                if (p->read_hunks) {
+                    p->last_read_hunk->next = entry;
+
+                } else {
+                    p->read_hunks = entry;
+                }
+
+                p->last_read_hunk = entry;
+
+                n -= size;
+
+                /* the copy input filter */
+
+                if (p->input_filter == NULL) {
+                    ngx_test_null(h, ngx_alloc_hunk(p->pool), NGX_ERROR);
+                    ngx_memcpy(h, entry->hunk, sizeof(ngx_hunk_t));
+                    h->shadow = entry->hunk;
+                    h->type |= NGX_HUNK_LAST_SHADOW;
+
+                    ngx_test_null(temp, ngx_alloc_chain_entry(p->pool),
+                                  NGX_ERROR);
+                    temp->hunk = h;
+                    temp->next = NULL;
+
+                    if (p->in_hunks) {
+                        p->last_in_hunk->next = temp;
+
+                    } else {
+                        p->in_hunks = temp;
+                    }
+
+                    p->last_in_hunk = temp;
+                }
+
+            } else {
+                entry->hunk->last += n;
+                p->free_hunks = entry;
+
+                n = 0;
+            }
+        }
+
+ngx_log_debug(p->log, "rest chain: %08X" _ entry);
+
+        /* if the rest hunks are shadow then move them to a shadow chain
+           otherwise add them to a free chain */
+
+        if (entry) {
+            if (entry->hunk->shadow) {
+                p->shadow_hunks = entry;
+
+            } else {
+                if (p->free_hunks) {
+                    p->free_hunks->next = entry;
+
+                } else {
+                    p->free_hunks = entry;
+                }
+            }
+
+            p->block_upstream = 0;
+            break;
+        }
+
+        /* the input filter i.e. that moves HTTP/1.1 chunks
+           from a read chain to an incoming chain */
+
+        if (p->input_filter) {
+            if (p->input_filter(p) == NGX_ERROR) {
+                return NGX_ERROR;
+            }
+        }
+    }
+
+ngx_log_debug(p->log, "eof: %d block: %d" _
+              p->upstream_eof _ p->block_upstream);
+
+    /* if there's the end of upstream response then move
+       the partially filled hunk from a free chain to an incoming chain */
+
+    if (p->upstream_eof) {
+        p->upstream->read->ready = 0;
+
+        if (p->free_hunks
+            && p->free_hunks->hunk->pos < p->free_hunks->hunk->last)
+        {
+            if (p->input_filter) {
+                if (p->input_filter(p) == NGX_ERROR) {
+                    return NGX_ERROR;
+                }
+
+            } else {
+                entry = p->free_hunks;
+
+                if (p->in_hunks) {
+                    p->last_in_hunk->next = entry;
+
+                } else {
+                    p->in_hunks = entry;
+                }
+
+                p->last_in_hunk = entry;
+            }
+
+            p->free_hunks = entry->next;
+            entry->next = NULL;
+        }
+
+#if 0
+        /* free the unneeded hunks */
+
+        for (entry = p->free_hunks; entry; entry = ce->next) {
+            ngx_free_hunk(p->pool, entry->hunk);
+        }
+#endif
+
+        if (p->in_hunks) {
+            p->last_in_hunk->hunk->type |= NGX_HUNK_LAST;
+
+        } else if (p->out_hunks) {
+            p->last_out_hunk->hunk->type |= NGX_HUNK_LAST;
+        }
+    }
+
+    if (p->cachable) {
+        if (p->in_hunks) {
+            rc = ngx_event_proxy_write_chain_to_temp_file(p);
+            if (rc != NGX_OK) {
+                return rc;
+            }
+        }
+
+        if (p->out_hunks && p->client->write->ready) {
+            rc = ngx_event_proxy_write_to_client(p);
+        }
+
+    } else if ((p->out_hunks || p->in_hunks) && p->client->write->ready) {
+        rc = ngx_event_proxy_write_to_client(p);
+    }
+
+    p->level--;
+
+ngx_log_debug(p->log, "level: %d" _ p->level);
+
+    if (p->level == 0 && p->block_upstream) {
+        p->upstream->read->blocked = 1;
+        if (ngx_del_event(p->upstream->read, NGX_READ_EVENT, 0) == NGX_ERROR) {
+            return NGX_ERROR;
+        }
+
+        return NGX_AGAIN;
+    }
+
+    if (p->upstream_eof) {
+        return NGX_OK;
+    } else {
+        return NGX_AGAIN;
+    }
+}
+
+
+int ngx_event_proxy_write_to_client(ngx_event_proxy_t *p)
+{
+    int           rc;
+    ngx_hunk_t   *h;
+    ngx_chain_t  *entry;
+
+ngx_log_debug(p->log, "write to client");
+
+    h = p->busy_hunk;
+
+    for ( ;; ) {
+
+        if (h == NULL) {
+            if (p->out_hunks) {
+                entry = p->out_hunks;
+                p->out_hunks = entry->next;
+                h = entry->hunk;
+
+                if (p->shadow_hunks) {
+                    if (p->shadow_hunks->hunk == h->shadow) {
+                        p->shadow_hunks = p->shadow_hunks->next;
+                    }
+                }
+
+                entry->next = NULL;
+
+            } else if (p->cachable == 0 && p->in_hunks) {
+                entry = p->in_hunks;
+                p->in_hunks = entry->next;
+                h = entry->hunk;
+                entry->next = NULL;
+            }
+
+ngx_log_debug(p->log, "event proxy write hunk: %08X:%08X" _ h _ h->pos);
+
+            if (h == NULL) {
+                if (p->upstream->read->ready) {
+                    rc = ngx_event_proxy_read_upstream(p);
+                }
+
+                return NGX_OK;
+            }
+        }
+
+ngx_log_debug(p->log, "event proxy write: %d" _ h->last - h->pos);
+
+        rc = p->output_filter(p->output_data, h);
+
+ngx_log_debug(p->log, "event proxy: %d" _ rc);
+
+        if (rc == NGX_ERROR) {
+            return NGX_ERROR;
+        }
+
+        if (rc == NGX_AGAIN
+            || (h->type & NGX_HUNK_IN_MEMORY && h->pos < h->last)
+            || (h->type & NGX_HUNK_FILE && h->file_pos < h->file_last))
+        {
+            if (p->busy_hunk == NULL) {
+                p->busy_hunk = h;
+            }
+            return NGX_AGAIN;
+        }
+
+        p->busy_hunk = NULL;
+
+        /* if the complete hunk is the file hunk and it has a shadow hunk
+           then add a shadow hunk to a free chain */
+
+        if (h->type & NGX_HUNK_FILE) {
+            if (p->cachable == 0 && p->out_hunks == NULL) {
+                p->temp_offset = 0;
+            }
+        }
+
+        if ((h->type & NGX_HUNK_LAST_SHADOW) == 0) {
+            h = NULL;
+            continue;
+        }
+
+
+        h->shadow->shadow = NULL;
+        h = h->shadow;
+
+#if 0
+        /* free the unneeded hunk */
+
+        if (p->upstream_eof) {
+            ngx_free_hunk(p->pool, h);
+            continue;
+        }
+#endif
+
+        h->pos = h->last = h->start;
+
+        entry->hunk = h;
+
+        /* if the first hunk in a free chain is partially filled
+           then add the complete hunk after the first free hunk */
+
+        if (p->free_hunks
+            && p->free_hunks->hunk->start != p->free_hunks->hunk->last)
+        {
+            entry->next = p->free_hunks->next;
+            p->free_hunks->next = entry;
+
+        } else {
+            entry->next = p->free_hunks;
+            p->free_hunks = entry;
+        }
+
+        h = NULL;
+    }
+}
+
+
+int ngx_event_proxy_write_chain_to_temp_file(ngx_event_proxy_t *p)
+{
+    int           i, rc, size;
+    ngx_hunk_t   *h;
+    ngx_chain_t  *entry, *next, *saved_in, *saved_read;
+
+ngx_log_debug(p->log, "write to file");
+
+    if (p->temp_file->fd == NGX_INVALID_FILE) {
+        rc = ngx_create_temp_file(p->temp_file, p->temp_path, p->pool,
+                                  p->number, p->random, p->cachable);
+
+        if (rc != NGX_OK) {
+            return rc;
+        }
+
+        if (p->cachable == 0 && p->temp_file_warn) {
+            ngx_log_error(NGX_LOG_WARN, p->log, 0, p->temp_file_warn);
+        }
+    }
+
+    if (p->cachable == 0) {
+
+        entry = p->read_hunks;
+        size = 0;
+
+        do {
+            size += entry->hunk->last - entry->hunk->pos;
+            if (size >= p->file_block_size) {
+                break;
+            }
+            entry = entry->next;
+
+        } while (entry);
+
+        saved_read = entry->next;
+        entry->next = NULL;
+
+        if (saved_read) {
+            for (entry = p->in_hunks; entry->next; entry = entry->next) {
+                if (entry->next->hunk->shadow == saved_read->hunk) {
+                    break;
+                }
+            }
+            saved_in = entry->next;
+            entry->next = NULL;
+
+        } else {
+            saved_in = NULL;
+        }
+
+    } else {
+        saved_read = NULL;
+        saved_in = NULL;
+    }
+
+    if (ngx_write_chain_to_file(p->temp_file, p->in_hunks, p->temp_offset,
+                                p->pool) == NGX_ERROR) {
+        return NGX_ERROR;
+    }
+
+    for (entry = p->in_hunks; entry; entry = next) {
+        next = entry->next;
+        entry->next = NULL;
+
+        h = entry->hunk;
+        h->type |= NGX_HUNK_FILE;
+        h->file = p->temp_file;
+        h->file_pos = p->temp_offset;
+        p->temp_offset += h->last - h->pos;
+        h->file_last = p->temp_offset;
+
+ngx_log_debug(p->log, "event proxy file hunk: %08X:%08X" _ h _ h->pos);
+
+        if (entry->hunk->type & NGX_HUNK_LAST_SHADOW) {
+            entry->hunk->shadow->last = entry->hunk->shadow->pos;
+        }
+
+        if (p->out_hunks) {
+            p->last_out_hunk->next = entry;
+
+        } else {
+            p->out_hunks = entry;
+        }
+
+        p->last_out_hunk = entry;
+    }
+
+    p->shadow_hunks = p->read_hunks;
+
+    p->read_hunks = saved_read;
+    p->in_hunks = saved_in;
+
+    return NGX_OK;
+}